Phosphorus-containing carboxylic acid derivatives process for preparations thereof and flame retardant

ABSTRACT

There are disclosed a phosphorus-containing carboxylic acid derivative which has a group containing phosphorus atom and has in its molecule, a group represented by the following formula (1): 
                         
wherein R 1 , R 2  and R 3  are each hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms, and Y is oxygen atom or sulfur atom; a process for producing the derivative; and a flame retardant comprising the foregoing derivative as an effective ingredient. The present invention can provide the phosphorus-containing carboxylic acid derivative and a flame retardant which are each excellent in solubility in an organic solvent, compatibility with a variety of resins, stability and flame retardancy.

TECHNICAL FIELD

The present invention relates to a phosphorus-containing carboxylic acidderivative which is utilized as a resin molded article, flame retardant,coloring preventive agent, heat resistance-imparting agent, curing agentfor a thermosetting resin and the like; a process for producing theabove-mentioned derivative; and usage thereof. More particularly, thepresent invention concerns with a phosphorus-containing carboxylic acidderivative which is excellent in solubility in an organic solvent,compatibility with a variety of resin and storage stability in blendingwith a resin, and which can impart a favorable and suitable resincomposition to a resin molded article, covering material, adhesive andthe like each requiring flame retardancy; a process for producing theabove-mentioned derivative; and usage such as a flame retardant.

BACKGROUND ART

In general, a synthetic resin molded article which requires flameretardancy is blended with any of various flame retardants such as aphosphorus based flame retardant and a halogen based flame retardant.These flame retardants are required to be resistant to the heat, actingin the case of molding and processing a synthetic resin or using aproduct after molding and at the same time, are desired not to impairthe performances inherent in the synthetic resin such as waterresistivity and physical performances.

However, the phosphorus-containing compounds which have hitherto beenused as a flame retardant suffer from such defects that impair physicalcharacteristics of a synthetic resin, deteriorate the stability andwater resistivity and so forth, since most of the compounds have beeneach an additive-type flame retardant. In addition, since most of thephosphorus-containing compounds that are used each as an additive-typeflame retardant are poor in compatibility with a resin, there have beenbrought about the problem that the compounds are difficult tohomogeneously blend in the resin, even if homogeneous blending ispossible, the problem that the flame retardant bleeds out from themolded article after molding, thus failing to maintain the workingeffect thereof and also the problem on external appearance.

In order to overcome the above-mentioned problems, aphosphorus-containing epoxy resin is proposed {refer to Japanese PatentApplication Laid-Open No. 279258/1999 (Hei 11)}. The aforesaid epoxyresin, in which phosphorus-containing groups are chemically bonded tothe resin matrix after molding, can become a flame retardant excellentin water resistivity and stability, while maintaining resincharacteristics to some extent. Nevertheless, the phosphorus-containingepoxy resin is inferior in solubility in much of organic solvents and incompatibility with a variety of resins, thereby limiting the blendingformulations thereof. It also involves the problem that it isinapplicable alone to the purpose of the use which requires high flameretardancy because of a low concentration (2.5% by weight or lower) ofphosphorus atoms that can be blended in a resin and the like.

On the other hand, although some consideration is given to aphosphorus-containing carboxylic acid having phosphorus atoms andfurther a carboxylic group which reacts with an epoxy group as anexcellent reactive flame retardant, the carboxylic acid involves theproblem about general purpose properties because of its being inferiorin solubility in much of organic solvents and in compatibility with avariety of resins as mentioned hereinbefore. In addition, since thecarboxylic group and a reactive group are prone to react with eachother, the carboxylic acid further creates the problem about thestability in that a composition in which the phosphorus-containingcarboxylic acid and a compound containing the aforesaid reactive groupcoexist causes gelation during storage, limits a usable hour fromblending to application and so forth.

Moreover a process for producing the above-mentionedphosphorus-containing carboxylic acid involves several problems asdescribed hereunder. The phosphorus-containing carboxylic acid,especially a phosphorus-containing dicarboxylic acid has been produced,for instance, by allowing a phosphorus compound bearing a P—H bond suchas 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to react with anunsaturated dicarboxylic acid such as fumaric acid, maleic acid oritaconic acid. The reaction is that called Michael addition reactionbetween the P—H bond in the phosphorus compound and C═C double bond inthe unsaturated dicarboxylic acid. The reaction has been put intopractice by mixing the phosphorus compound with the unsaturateddicarboxylic acid and heating the resultant mixture to a temperature inthe range of 160 to 200° C., but has suffered the disadvantages ofdifficult temperature control due to the reaction being exothermic andalso difficult separation of the phosphorus-containing dicarboxylic acidobtained after the reaction from the starting raw materials containingthe phosphorus compound and the unsaturated dicarboxylic acid. Hence, inspite of being an extremely useful substance, the phosphorus-containingdicarboxylic acid is poor in productivity, is expensive in productioncost and contains a large amount of the starting raw materials asimpurities, whereby the practical application thereof is generallydifficult.

In order to overcome the above-mentioned problems, there is disclosed aprocess for synthesizing the phosphorus-containing dicarboxylic acid ata reaction temperature in the range of 100 to 200° C. by the use of alower saturated aliphatic monocarboxylic acid having 1 to 5 carbon atomsas a solvent {refer to Japanese Patent Application Laid-Open No.176171/1996 (Hei 8)}. According to the above-mentioned productionprocess, it is made possible to obtain a highly purephosphorus-containing carboxylic acid in high yield by relativelyremoving generated heat upon the reaction of the phosphorus-containingcarboxylic acid at a comparatively low temperature. However, theaforesaid lower saturated aliphatic monocarboxylic acid, which is ahighly corrosive solvent having strong irritating-smell, is problematicin that perfect removal of the acid is difficult, thereby making itdifficult to perfectly eliminating the irritating-smell even if cleaningis carried out repeatedly with great care by using a suitable solvent.

Moreover in the case where the carboxylic group in thephosphorus-containing dicarboxylic acid is used for the purpose ofreacting with an other functional group, residual carboxylic group inthe saturated aliphatic monocarboxylic acid reacts in the same manner asabove, and for instance, when the carboxylic group is used as comonomerfor polyester, there is a fear of causing the problem of unreasonablylowering the molecular weight of the objective polyester.

In such circumstances, there has eagerly been desired the development ofa process for producing a highly pure phosphorus-containing carboxylicacid in high yield which process can facilitate industrial reactioncontrol at a relatively low temperature and can also facilitate solventremoval.

DISCLOSURE OF THE INVENTION

Much attention, which has been paid to the above-mentioned problems withthe prior arts, led to the accomplishment of the present invention. Thusan object of the present invention is to provide a phosphorus-containingcarboxylic acid derivative which is excellent in solubility in anorganic solvent, compatibility with a variety of synthetic resins andstorage stability and which can exert excellent characteristics such asflame retardancy and the like; a process for producing theabove-mentioned derivative; and usage such as a flame retardant.

Another object of the present invention is to provide a process which iscapable of producing in high yield, a highly pure odor-freephosphorus-containing dicarboxylic acid being one of raw materials for aphosphorus-containing carboxylic acid derivative at a low reactiontemperature as compared with prior arts, and also capable of removingthe heat generated upon reaction and at the same time, facilitatingremoval of a solvent used in the reaction.

In order to achieve the above-mentioned objects, the present inventorshave accumulated intensive extensive research and investigation. As aresults it has been found that the objects can be attained by providinga phosphorus-containing carboxylic acid derivative having specificstructure, a resin composition using the same, a resin molded articleand a process for producing the aforesaid phosphorus-containingcarboxylic acid derivative.

That is to say, the present invention pertains to the following:

[1] A flame retardant comprising as an effective ingredient, aphosphorus-containing carboxylic acid derivative which has a groupcontaining phosphorus atom and has in its molecule, a group representedby the following formula (1):

wherein R¹, R² and R³ are each hydrogen atom or a hydrocarbon grouphaving 1 to 18 carbon atoms, and Y is oxygen atom or sulfur atom.[2] A phosphorus-containing carboxylic acid derivative which has a groupcontaining phosphorus atom and has in its molecule, a group representedby the following formula (1):

wherein R¹, R² and R³ are each hydrogen atom or a hydrocarbon grouphaving 1 to 18 carbon atoms, and Y is oxygen atom or sulfur atom.[3] The phosphorus-containing carboxylic acid derivative as set forth inthe preceding item [2] wherein the group represented by the formula (1)is a group represented by the following formula (2):

wherein R¹, R² and R³ are each hydrogen atom or a hydrocarbon grouphaving 1 to 18 carbon atoms, R⁴ is a hydrocarbon group having 1 to 18carbon atoms, R³ and R⁴ may be bonded to each other, and Y is oxygenatom or sulfur atom.[4] The phosphorus-containing carboxylic acid derivative as set forth inthe preceding item [2] wherein the group represented by the formula (1)is a group represented by the following formula (3):

wherein R⁴ is a hydrocarbon group having 1 to 18 carbon atoms.[5] A polyhemiacetal type phosphorus-containing carboxylic acidderivative within the categories of the preceding item [2] comprises asa repeating unit, a group represented by the following formula (4):

wherein R¹, R² and R³ are each hydrogen atom or a hydrocarbon grouphaving 1 to 18 carbon atoms, Y is oxygen atom or sulfur atom, R⁵ is abivalent organic group having 1 to 25 carbon atoms, and R⁶ is a bivalentorganic group which has 1 to 30 carbon atoms and comprises a groupcontaining phosphorus atoms.[6] The polyhemiacetal type phosphorus-containing carboxylic acidderivative as set forth in the preceding item [5] wherein the grouprepresented by the formula (4) is a group represented by the followingformula (5):

wherein R⁵ is a bivalent organic group having 1 to 25 carbon atoms, andR⁶ is a bivalent organic group which has 1 to 30 carbon atoms andcomprises a functional group containing phosphorus atoms.[7] A flame retardant comprises as an effective ingredient, thephosphorus-containing carboxylic acid derivative as set forth in any ofthe preceding items [2] to [6].[8] A process for producing a phosphorus-containing carboxylic acidderivative as set forth in any of the preceding items [2] to [6] whichcomprises a step of reacting a phosphorus-containing carboxylic acidcompound bearing both a carboxylic group and phosphorus atom with avinyl ether compound, a vinyl thioether compound, a divinyl ethercompound or a divinyl thioether compound.[9] The process for producing a phosphorus-containing dicarboxylic acidderivative as set forth in the preceding item [8] wherein thephosphorus-containing carboxylic acid compound is produced by subjecting(A) a P—H group-containing phosphorus compound and (B) an unsaturatedcarboxylic acid each as a starting raw material to Michael additionreaction by (i) using acetonitrile or methoxypropyl acetate as aprincipal reaction solvent at (ii) a reaction temperature in the rangeof 50 to 150° C.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an infrared absorption spectrum of the product obtained inExample 1;

FIG. 2 is a nuclear magnetic resonance spectrum of the product obtainedin Example 1;

FIG. 3 is an infrared absorption spectrum of the product obtained inExample 2;

FIG. 4 is an infrared absorption spectrum of the product obtained inExample 3;

FIG. 5 is an infrared absorption spectrum of the product obtained inExample 4;

FIG. 6 is an infrared absorption spectrum of the product obtained inExample 5;

FIG. 7 is a nuclear magnetic resonance spectrum of the product obtainedin Example 5;

FIG. 8 is an infrared absorption of the product obtained in Example 6;

FIG. 9 is a nuclear magnetic resonance spectrum of the product obtainedin Example 6;

FIG. 10 is an infrared absorption spectrum of the product obtained inExample 7;

FIG. 11 is a nuclear magnetic resonance spectrum of the product obtainedin Example 7;

FIG. 12 is an infrared absorption spectrum of the product obtained inExample 8; and FIG. 13 is an infrared absorption spectrum of the productobtained in Example 9.

THE MOST PREFERRED EMBODIMENT TO CARRY OUT THE INVENTION

In the following, the present invention will be described in moredetail.

The phosphorus-containing carboxylic acid derivative according to thepresent invention has a group containing phosphorus atom and a grouprepresented by the following formula (1):

wherein R¹, R² and R³ are each hydrogen atom or a hydrocarbon grouphaving 1 to 18 carbon atoms, and Y is oxygen atom or sulfur atom.

The group represented by the formula (1) is exemplified, for instance,by the group represented by the following formula (2):

wherein R¹, R² and R³ are each hydrogen atom or a hydrocarbon grouphaving 1 to 18 carbon atoms, R⁴ is a hydrocarbon group having 1 to 18carbon atoms, R³ and R⁴ may be bonded to each other, and Y is oxygenatom or sulfur atom.

It is possible in the present invention to use as the group representedby the aforesaid formula (1) or (2), the group represented by thefollowing formula (6):

wherein R¹ and R² are each hydrogen atom or a hydrocarbon group having 1to 18 carbon atoms, R³ is a hydrocarbon group having 1 to 18 carbonatoms, and Y is oxygen atom or sulfur atom.

The group represented by the foregoing formula (1) is furtherexemplified by the group represented by the following formula (3):

wherein R⁴ is a hydrocarbon group having 1 to 18 carbon atoms.

The group represented by any of the formulae (1) to (3) and (6) iscontained in 1 to 10 numbers, preferably 1 to 4 numbers per one moleculeof the phosphorus-containing carboxylic acid derivative. The number ofthe above-mentioned group, when exceeding 10 per one molecule of thephosphorus-containing carboxylic acid derivative, sometimes gives riseto deterioration in the reactivity between the phosphorus-containingcarboxylic acid and vinyl ether compound or vinyl thioether compoundthat are described hereinafter and also deterioration in compatibilityof the phosphorus-containing carboxylic acid derivative with a syntheticresin.

In addition, the phosphorus-containing carboxylic acid derivativeaccording to the present invention is exemplified by a hemiacetal typephosphorus-containing carboxylic acid derivative bearing the repeatingunit represented by the following formula (4):

wherein R¹, R² and R³ are each hydrogen atom or a hydrocarbon grouphaving 1 to 18 carbon atoms, Y is oxygen atom or sulfur atom, R⁵ is abivalent organic group having 1 to 25 carbon atoms, and R⁶ is a bivalentorganic group which has 1 to 30 carbon atoms and comprises a groupcontaining phosphorus atom.

Of the above-mentioned groups, the group represented by the followingformula (5) is preferable:

wherein R⁵ is a bivalent organic group having 1 to 25 carbon atoms, andR⁶ is a bivalent organic group which has 1 to 30 carbon atoms andcomprises a functional group containing phosphorus atom.

The phosphorus-containing carboxylic acid derivative having the grouprepresented by the above-mentioned formula (4) or formula (5) isexemplified by a phosphorus-containing polyhemiacetal resin having theaforesaid group as a repeating unit.

The weight average molecular weight of the above-mentionedphosphorus-containing polyhemiacetal resin is not specifically limited,but is usually in the range of 500 to 200,000, preferably in the rangeof 1,000 to 100,000.

As the phosphorus atom-containing group, use is made of the group inwhich phosphorus atoms therein are contained in a proportion ofpreferably 2 to 25% by weight, more preferably 3 to 15% by weight in thephosphorus-containing carboxylic acid derivative. The content of thephosphorus atoms, when being less than 2% by weight, sometimes givesrise to difficulty in imparting high flame retardancy to a resin moldedarticle which is obtained from the resin composition containing thephosphorus-containing carboxylic acid derivative, whereas the contentthereof, when being more than 25% by weight, brings about a tendency todeteriorate the resin characteristics of the objective resin moldedarticle.

It is preferable that the above-mentioned phosphorus atom-containinggroup be the group represented by any of the following formulae (7) to(10):

wherein R⁷ is hydrogen atom or an organic group having 1 to 20 carbonatoms, R⁸ is an organic group having 1 to 20 carbon atoms, and when bothR⁷ and R⁸ are an organic group, they may be bonded to each other;

wherein R⁹ and R¹⁰ are each hydrogen atom or an organic group having 1to 20 carbon atoms, and when both R⁹ and R¹⁰ are an organic group, theymay be bonded to each other;

wherein R¹¹ and R¹² are each an organic group having 1 to 20 carbonatoms, and may be bonded to each other.

wherein X¹ to X⁸, which are each an atom or group that may be the sameas or different from one another, are each hydrogen atom, a halogen atomor a hydrocarbon group having 1 to 5 carbon atoms.

Examples of the phosphorus atom-containing group represented by theabove-mentioned formula (9) include the group represented by any of thefollowing formulae (11) and (12):

wherein R²¹ and R²² are each hydrogen atom or a hydrocarbon group having1 to 12 carbon atoms.

In addition, the benzene ring in the formula (ii) may contain a halogenatom such as chlorine and bromine.

Further, examples of the phosphorus atom-containing group represented bythe above-mentioned formula (8) include the group represented by thefollowing formula (13):

wherein R²³ is a hydrocarbon group having 1 to 40 carbon atoms.

In addition, R¹⁰ in the formula (8) and R²³ in the formula (13) maycontain a halogen atom such as chlorine and bromine.

In what follows, some description will be given of processes forproducing the phosphorus-containing carboxylic acid derivative which hasthe chemical structure as described hereinbefore.

The phosphorus-containing carboxylic acid derivative is produced, asrepresented by the following reaction formula, by allowing aphosphorus-containing compound bearing both a carboxylic group andphosphorus atom to react (blocking) with a vinyl ether compound or avinyl thioether compound. That is to say, the above-mentionedphosphorus-containing carboxylic acid derivative is obtained by allowingthe carboxylic group of the phosphorus-containing compound to react withthe vinyl group of the vinyl ether compound or of the vinyl thioethercompound. Since it is comparatively easy to proceed with the reaction,the phosphorus-containing carboxylic acid derivative is obtained in highyield.

Being equilibrium reaction, the reaction is accelerated by the use ofthe vinyl ether compound or vinyl thioether compound in an amountsomewhat larger than that of the phosphorus-containing carboxylic acid,thereby enhancing the yield thereof. Specifically it is desirable thatthe molar equivalent ratio of the vinyl group of the vinyl ethercompound or vinyl thioether compound to the carboxylic groups of thephosphorus-containing carboxylic acid {molar equivalent ratio (vinylgroup/carboxylic group)} be set on 1/1 to 2/1. When the molar ratiothereof exceeds 2/1, it is sometimes made impossible to raise thereaction temperature and further proceed with the reaction and at thesame time, the production cost is unreasonably increased. In such acase, the molar equivalent ratio may be set on 0.5/1 to 1/1.

Examples of the phosphorus-containing carboxylic acid include thatrepresented by any of the following formulae (14) and (15). There isalso usable the phosphorus-containing carboxylic acid obtainable byallowing an unsaturated carboxylic acid such as acrylic acid or itaconicacid or an acid anhydride such as trimellitic anhydride to react withany of various phosphorus-containing compound:

In particular, the compound is useful which is obtainable by allowing acarboxylic acid bearing unsaturated group such as itaconic acid to reactwith the phosphorus-containing compound represented by the followingformula (16):

The content of the phosphorus atoms in the phosphorus-containingcarboxylic acid is preferably 3 to 30% by weight, more preferably 5 to20% by weight. The content thereof, when being less than 3% by weight,sometimes leads to difficulty in imparting high flame retardancy to amolded article obtained by molding a synthetic resin compositioncontaining the phosphorus-containing carboxylic acid, whereas thecontent thereof, when being more than 30% by weight, brings about thetendency to markedly deteriorate the characteristics inherent in amolded article. The vinyl ether compound and vinyl thioether compoundthat are to be used in the production process according to the presentinvention mean the compound represented by the following formula (17):

wherein R¹, R² and R³ are each hydrogen atom or a hydrocarbon grouphaving 1 to 18 carbon atoms, R⁴ is a hydrocarbon group having 1 to 18carbon atoms, and Y is oxygen atom or sulfur atom. Among them, usable isthe cyclic compound represented by the following formula (18):

wherein R¹ and R² are each hydrogen atom or a hydrocarbon group having 1to 18 carbon atoms, R¹² is a hydrocarbon group having 1 to 18 carbonatoms, and Y is oxygen atom or sulfur atom.

That is to say, the compound represented by the formula (18) is a cyclicvinyl ether compound such as a heterocyclic compound that bears onevinyl type double bond and in which oxygen atoms or sulfur atomsconstitute heteroatoms.

Specific examples of the compound represented by any of the formulae(17) and (18) include aliphatic monovinyl ether compounds such asmethylvinyl ether, ethylvinyl ether, isopropylvinyl ether, n-propylvinylether, n-butylvinyl ether, isobutylvinyl ether, tert-butylvinyl ether,2-ethylhexylvinyl ether and cyclohexylvinyl ether; aliphatic monovinylthioether compounds corresponding to the above-mentioned ethercompounds, respectively; cyclic monovinyl ether compounds such as2,3-dihydrofuran, 3,4-dihydrofuran, 2,3-dihydro-2H-pyran,3,4-dihydro-2H-pyran, 3,4-dihydro-2-methoxy-2H-pyran,3,4-dihydro-4,4-dimethyl-2H-pyran-2-on, 3,4-dihydro-2-ethoxy-2H-pyranand 3,4-dihydro-2H-pyran-2-sodium carboxylate; cyclic monovinylthioether compounds corresponding to the ether compounds just mentioned.

The phosphorus-containing polyhemiacetal resin having the grouprepresented by any of the above-mentioned formulae (4) and (5) as therepeating unit is produced by allowing a phosphorus-containingdicarboxylic acid compound bearing both two carboxylic groups andphosphorus atom to react with a divinyl ether compound (this process issometimes referred to as blocking), as represented by the followingreaction formula:

In the foregoing reaction formula, R⁵ is a bivalent organic group having1 to 25 carbon atoms, m is an integer from 2 to 20, X and Y are each thenumber of moles of the starting raw materials, respectively whereinX/Y=1/2 to 2/1, Z¹ and Z² are each a residual group of reaction terminalderived from the divinyl ether and dicarboxylic acid.

In the above-mentioned process, the phosphorus-containing dicarboxylicacid compound may be blended with a phosphorus-atom-free dicarboxylicacid compound so that the resultant blend is reacted with the divinylether compound.

Since the reaction is polymerization addition reaction, it is possibleto adjust the molecular weight of the objective resin by controlling theblending ratio of the dicarboxylic acid compound to the divinyl ether.Moreover, the dicarboxylic acid compound and divinyl ether compound asstarting raw materials may be collectively fed to the reaction system toproceed with the reaction. Alternatively, they may be separately fedrespectively. For instance, the divinyl ether compound may be addeddropwise to the dicarboxylic acid compound. In this case, any of theabove-mentioned phosphorus-containing dicarboxylic acid, phosphorus-freedicarboxylic acid and divinyl ether compound may be used alone or incombination with at least one other.

Examples of the aforesaid phosphorus-containing dicarboxylic acidinclude the compound represented by the above-mentioned formula (15).Also usable is the phosphorus-containing carboxylic acid obtainable byallowing an unsaturated dibasic carboxylic acid such as itaconic acid oran acid anhydride such as trimellitic anhydride to react with any ofvarious phosphorus-containing compound.

In particular, the compound is useful which is obtainable by allowing acarboxylic acid bearing an unsaturated group such as itaconic acid toreact with the phosphorus-containing compound represented by theforegoing formula (16).

In the case where use is made of the group represented by any of theabove-mentioned formulae (4) and (5) as the repeating unit, the groupmay be used alone or in combination with at least one other or may beincorporated with a repeating unit other than the repeating unitrepresented by any of the formulae (4) and (5). The resin contains therepeating unit represented by any of the formulae (4) and (5) in anamount of usually at least 10% by weight, preferably at least 20% byweight, particularly at least 50% by weight when used as a flameretardant.

The resin obtainable in the foregoing manner has the chemical structurerepresented by the following formula (19):

wherein R⁵ and R⁶ are each as previously defined, and Z¹ and Z² are eachhydrogen atom or the group represented by any of the following formulae(20), (21) and (22):

wherein R⁵ and R⁶ are each as previously defined.

The content of phosphorus atoms in the phosphorus-containingpolyhemiacetal resin is preferably 2 to 25% by weight, more preferably 3to 15% by weight. The content thereof, when being less than 2% byweight, sometimes leads to difficulty in imparting high flame retardancyto a resin molded article obtained from a resin composition containingthe phosphorus-containing polyhemiacetal resin, whereas the contentthereof, when being more than 25% by weight, brings about the tendencyto deteriorate the resin characteristics of the resin molded article.

Examples of the phosphorus atom-free dicarboxylic acid compound includealiphatic dicarboxylic acid having 2 to 25 carbon atoms such as maleicacid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid,chlorinated maleic acid, HET acid, succinic acid, adipic acid, azelaicacid sebacic acid and decamethylene dicarboxylic acid; aromaticdicarboxylic acid such as phthalic acid, isophthalic acid, terephthalicacid, dichlorophthalic acid, tetrachlorophthalic acid,tetrachloroisophthalic acid and tetrachloroterephthalic acid; alicyclicdicarboxylic acid such as tetrahydrophthalic acid, hexahydrophthalicacid, methylhexahydrophthalic acid, hexahydroisophthalic acid andhexahydroterephthalic acid.

In addition, examples of the phosphorus atom-free dicarboxylic acidcompound include a dicarboxylic acid compound half ester body which isobtained by addition reaction of one mol of a diol and 2 moles of anacid anhydride in place of the dicarboxylic acid compound. Examples ofsuch diol include ethylene glycol, diethylene glycol, 1,2-propyleneglycol, 1,3-propylene glycol, 1,3-butalnediol, 1,4-butanediol,2,3-butanediol, 1,6-hexanediol, pentanediol, dimethylbutanediol,hydrogenated bisphenol A, bisphenol A, hydrogenated bisphenol F,bisphenol F, neopentyl glycol, 1,8-octanediol, 1,4-cyclohexanedimethanol and 2-methyl-1,3-propanediol. Examples of the acid anhydridewhich is used for the half ester body include an acid anhydride from adicarboxylic acid such as succinic acid, glutaric acid, phthalic acid,maleic acid, dichlorophthalic acid, tetrachlorophthalic acid,tetrahydrophthalic acid, hexahydrophthalic acid andmethylhexahydrophthalic acid.

Specific examples of the divinyl ether compound to be used for theproduction of the phosphorus-containing polyhemiacetal resin accordingto the present invention include trimethylene glycol divinyl ether,triethylene glycol divinyl ether (TEGDVE),1,4-bisvinyloxymethylcyclohexene, ethylene glycol divinyl ether,polyethylene glycol divinyl ether, 1,4-butanediol divinyl ether(1,4BDVE), pentanediol divinyl ether, hexanediol divinyl ether,1,4-cyclohexane dimethanol divinyl ether (CHDVE) and a thioethercompound which corresponds to any of the above-exemplified divinyl ethercompound.

The phosphorus-containing carboxylic acid derivative according to thepresent invention is obtainable by allowing the above-mentionedphosphorus-containing carboxylic acid to react with the vinyl ethercompound, vinyl thioether compound, vinyl thioether compound or divinylthioether compound at a temperature in the range of room temperature to150° C. It is possible in this case to use an acid catalyst for thepurpose of accelerating the reaction. Examples of such catalyst includean acidic phosphoric acid ester compound represented by the followingformula (23):

wherein R is an alkyl group having 3 to 10 carbon atoms, a cycloalkylgroup or an aryl group, and m is 1 or 2.

Specific examples of the acidic phosphoric acid ester compoundrepresented by the above-mentioned formula (23) include phosphoric acidmonoester and phosphoric acid diester each of a primary alcohol such asn-propanol, n-butanol, n-hexanol, n-octanol and 2-ethylhexanol, andsecondary alcohol such as isopropanol, 2-butanol, 2-hexanol, 2-octanoland cyclohexanol.

Moreover, an organic solvent may be used for the purpose of uniformizingthe reaction system and at the same time, facilitating the reaction.Examples of such organic solvent include aromatic hydrocarbons such asbenzene, toluene, xylene, ethylbenzene, aromatic petroleum naphtha,tetralin, turpentine oil, Solvesso # 100 (trade name available fromExxon Chemical Co., Ltd.) and Solvesso #150 (trade name available fromExxon Chemical Co., Ltd.); ethers such as dioxane and tetrahydrofuran;esters and ether esters such as methyl acetate, ethyl acetate, n-propylacetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, sec-butylacetate, amyl acetate, methoxybutyl acetate and methoxypropyl acetate(PMAc); ketones such as acetone, methyl ethyl ketone, methyl isobutylketone, methyl amyl ketone, cyclohexanone, isophorone, mesitil oxide,methyl isoamyl ketone, ethyl-n-butyl ketone, ethyl amyl ketone,diisobutyl ketone, diethyl ketone, methyl propyl ketone and diisobutylketone; phosphoric acid esters such as trimethyl phosphate, triethylphosphate and tributyl phosphate; nitrogen-containing compound such asN,N-dimethylformamide, N,N-dimethylacetoamide, N-methyl-2-pyrrolidone,N-methylmorpholine and acetonitrile; and dimethylsulfoxide.

One of the objects of the present invention is to provide a processcapable of producing a highly pure odorless phosphorus-containingcarboxylic acid, especially phosphorus-containing dicarboxylic acid inhigh yield at a low reaction temperature as compared with a conventionaltemperature, while enabling removal of heat generated upon reaction andfacilitating solvent removal, said carboxylic acid being a starting rawmaterial for the phosphorus-containing carboxylic acid derivative.

As mentioned hereinbefore, Michael addition reaction has heretofore beenthought to proceed only under a high reaction temperature in the rangeof 160 to 250° C. However, as the result of intensive extensive researchand investigation made by the present inventors on the addition reactionbetween similar phosphorus compound and C═C double bond of anunsaturated aliphatic carboxylic acid, it has been discovered that theaforesaid reaction proceeds at a comparatively low reaction temperaturein the range of 50 to 150° C. under a specific reaction conditions, andit has been found out that Michael addition reaction proceeds by the useof acetonitrile or methoxypropyl acetate as a solvent for the aforesaidreaction. That is to say, the present invention also provides a processfor producing a phosphorus-containing carboxylic acid compound whichcomprises subjecting (A) a P—H group-containing phosphorus compound and(B) an unsaturated carboxylic acid each as a starting raw materials toMichael addition reaction by (i) using acetonitrile or methoxypropylacetate as a principal reaction solvent at (ii) a reaction temperaturein the range of 50 to 150° C. The above-mentioned process is preferablyused for the production of a phosphorus-containing carboxylic acid to beused as a starting raw material in the case of producing thephosphorus-containing carboxylic acid derivative according to thepresent invention.

In the above-described production process, the component (A) as thestarting raw material is the compound represented by the followingformula (24):

wherein R¹⁵ and R¹⁶ are each hydrogen atom or a same or differentorganic group having 1 to 20 carbon atoms which may be bonded to eachother to form a ring, and n1 and n2 are each independently 0 or 1; thecomponent (B) as the starting raw material is fumaric acid, maleic acidor itaconic acid each represented by the following formula (25):

wherein R¹⁷ is hydrogen atom or —COOH group, when R¹⁷ is hydrogen atom,R¹⁸ is —CH₂COOH group, and when R¹⁷ is —COOH group, R¹⁸ is hydrogenatom; and the product is represented by the following formula (26):

wherein R¹⁵, R¹⁶, R¹⁷, R¹⁸ n1 and n2 are the same as defined in theforegoing description.

In the formula (24), R¹⁵ and R¹⁶ may be same or different organic grouphaving 1 to 20 carbon atoms which is exemplified by methyl group, ethylgroup, n-propyl group, isopropyl group, n-butyl group, isobutyl group,sec-butyl group, tert-butyl group, n-hexyl group, iso-hexyl group,n-heptyl group, isoheptyl group, n-octyl group, isooctyl group,n-dodecyl group, isododecyl group, n-octadecyl group, iso-octadecylgroup, cyclopentyl group, cyclohexyl group, phenyl group, benzyl groupand the like, and R¹⁵ and R¹⁶ may be bonded to each other.

The P—H group-containing phosphorus compound as the component (A) ispreferably exemplified by9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide represented by theforegoing formula (16) or diphenylhydrogen phosphite for excellent waterresistivity of the phosphorus-containing dicarboxylic acid as theproduct after the reaction, and also exemplified by diethylhydrogenphosphite for excellent weather resistance.

The unsaturated carboxylic acid as the component (B) is exemplified byacrylic acid, methacrylic acid, mesaconic acid, citraconic acid,cyclohexanecarboxylic acid, fumaric acid, maleic acid or itaconic acid.Of these, fumaric acid, maleic acid and itaconic acid are preferable.

The acetonitrile as the solvent has a boiling point of about 81° C., andthe methoxypropyl acetate has a boiling point of about 146° C., in whichreagent grade solvent and industrial grade solvent are both usable.

The reaction atmosphere includes atmospheric pressure or pressurizedpressure, and a reaction temperature in the range of 50 to 150° C.,preferably 60 to 150° C. The reaction temperature, when being lower than50° C., requires an unreasonably long reaction time, whereas thetemperature, when being higher than 150° C., brings about an anxiety offierce coloring of the objective product.

The reaction is that termed Michael addition reaction between P—H groupof the phosphorus compound and C═C double bonds of an unsaturatedcarboxylic acid, and is represented as the following:

wherein R¹⁵, R¹⁶, R¹⁷, R¹⁸, n1 and n2 each are the same as previouslydefined.

Acetonitrile and methoxypropyl acetate are each a solvent having highgeneral-purpose properties, and solubilize the phosphorus compound andunsaturated dicarboxylic acid. However, much of thephosphorus-containing dicarboxylic acids as the product are insoluble inacetonitrile and methoxypropyl acetate and thus, it is possible topurify the product from the starting raw materials only by filtrationafter the reaction. In the case of completely removing residualacetonitrile, removal thereof under vacuum is facilitated, since it hasa boiling point of about 80° C. under atmospheric pressure.

It is known that the reaction is exothermic. The heat generated upon thereaction has hitherto been the cause of uncontrollable suddentemperature rise in this reaction. Nevertheless it is possible for theprocess according to the present invention to suppress theuncontrollable sudden temperature rise by proceeding with the reactionunder reflux at a temperature lower than in the prior arts, since theboiling points under atmospheric pressure of acetonitrile andmethoxypropyl acetate are respectively about 80° C. and about 146° C. Inaddition, the reaction under comparatively low temperature makes itpossible to obtain phosphorus-containing dicarboxylic acid withoutunfavorable coloring.

It is possible for the above-described reaction to suppress the reactiontemperature to a lower level than 50 to 150° C. in the prior arts.However in the case of carrying out the reaction at 84 to 150° C.,reaction under a pressurized pressure is necessary because ofacetonitrile having a boiling point of about 80° C. under atmosphericpressure.

In the foregoing reaction, acetonitrile or methoxypropyl acetate, whichis used as a solvent, may be used in combination with an other organicsolvent for the purpose of regulating the boiling point thereof,viscosity thereof, solubility of starting raw materials and the like.Examples of such solvent include aromatic hydrocarbons such as benzene,toluene, xylene, ethylbenzene, aromatic petroleum naphtha, tetralin,turpentine oil, Solvesso # 100 (trade name; available from ExxonChemical Co., Ltd.) and Solvesso # 150 (trade name; available from ExxonChemical Co., Ltd.); ethers such as dioxane and tetrahydrofuran; estersand ether esters such as methyl acetate, ethyl acetate, n-propylacetate, isopropyl acetate, n-butyl acetate, isobutyl acetate,tert-butyl acetate, amyl acetate, methoxybutyl acetate and methoxypropylacetate (PMAc); ketones such as acetone, methyl ethyl ketone, methylisobutyl ketone, methyl amyl ketone, cyclohexanone, isophorone, mesitiloxide, methyl isoamyl ketone, ethyl-n-butyl ketone, ethyl amyl ketone,diisobutyl ketone, diethyl ketone, methyl propyl ketone and diisobutylketone; phosphoric acid esters such as trimethyl phosphate, triethylphosphate and tributyl phosphate; dimethylsulfoxide; andN,N-dimethylformamide.

The above-exemplified solvent other than the acetonitrile andmethoxypropyl acetate is added in an amount of preferably at most 60% byweight based on the whole amount of the solvents, and when added by morethan 60% by weight based thereon, sometimes leads to failure to assurethe working effect of the present invention.

In the above-mentioned reaction, the amount of the acetonitrile ormethoxypropyl acetate is preferably 10 to 80% by weight based on thetotal feed amount, particularly preferably 20 to 60% by weight basedthereon. The amount of the acetonitrile or methoxypropyl acetate, whenbeing less than 10% by weight based thereon, sometimes brings aboutdeterioration in reactivity due to excessively high viscosity of thereaction system, and difficulty in solubilizing at room temperature, thephosphorus compound and unsaturated dicarboxylic acid that are each anunreacted starting raw material, thereby deteriorating the refiningefficiency, whereas the aforesaid amount, when being more than 80% byweight based thereon, sometimes leads not only to necessity for a longtime in solvent removal, but also to lowered rate of reactionaccompanying a decrease in the concentration of the reactants.

In the above-mentioned reaction, the molar feed ratio of the phosphoruscompound/unsaturated dicarboxylic acid, which is indicated by theequivalent ratio of P—H group/double bond, is usually set in the rangeof preferably 1/0.5 to 1/2. The molar feed ratio thereof, when beingmore than 1/0.5, in other words, excessive phosphorus compound, resultsin a large amount of residual phosphorus compound after the completionof the reaction, thus needing a large amount of the acetonitrile ormethoxypropyl acetate upon refining. On the contrary, The molar feedratio thereof, when being less than 1/2, in other words, excessiveunsaturated dicarboxylic acid, results in a large amount of residualunsaturated dicarboxylic acid after the completion of the reaction, thusneeding a large amount of the acetonitrile or methoxypropyl acetate uponrefining.

The above-mentioned reaction proceeds even in the absence of a catalyst,however for the purpose of accelerating the reaction, an acid catalyst,base catalyst, metal complex catalyst or radical generating agent isusable. A mixed catalyst by the combination thereof may also be used.

Examples of the acid catalyst as mentioned above include an acidicphosphoric acid ester compound represented by the foregoing formula(23).

Specific examples of the acidic phosphoric acid ester compoundrepresented by the formula (23) include phosphoric acid monoester andphosphoric acid diester each of a primary alcohol such as n-propanol,n-butanol, n-hexanol, n-octanol and 2-ethylhexanol, and secondaryalcohol such as isopropanol, 2-butanol, 2-hexanol, 2-octanol andcyclohexanol. A preferable example thereof is 2-ethylhexyl acidphosphate “AP-8” (trade name, available from Daihachi Chemical IndustryCo., Ltd.) represented by the following formula (27):

wherein R¹⁹ is 2-ethylhexyl group.

The base catalyst as mentioned above is exemplified by, but is notlimited to, monoamines, diamines, triamines, polyamines, cyclic amines,alcohol amines and ether amines, and is specifically exemplified bytriethylamine; N,N-dimethylcyclohexylamine;N,N,N′,N′-tetramethylethylenediamine;N,N,N′,N′-tetramethylpropane-1,3-diamine;N,N,N′,N′-tetramethylhexane-1,6-diamine;N,N,N′,N″,N″-pentamethyldiethylenetriamine;N,N,N′,N″,N″-pentamethyldipropylenetriamine; tetramethylguanidine;N,N-di(polyoxyethylene)stearylamine;N,N-di(polyoxyethylene)beef-tallow-amine; triethylenediamine;N,N′-dimethylpiperazine; N-methyl-N′-(2-dimethylamino)-ethylpiperazine;N-methylmorpholine; 1,8-diazabicyclo[5.4.0]undece-7-ene; pyridine;N-ethylmorpholine; N—(N′,N′-dimethylaminoethyl)-morpholine;1,2-dimethylimidazole; dimethylaminoethanol; dimethylaminoethoxyethanol;N,N,N′-trimethylaminoethylethanolamine;N-methyl-N′-(2-hydroxyethyl)-piperazine; N-(2-hydroxyethyl)-morpholine;bis(2-dimethylaminoethyl) ether; ethylene glycolbis-(3-dimethylaminopropyl) ether. Of these, pyridine and1,8-diazabicyclo[5.4.0]undece-7-ene are preferable.

An organometal complex in which an organic ligand is coordinated in acentral metal exemplifies the above-mentioned metal complex catalyst.Examples of the central metal include iron, nickel, cobalt, ruthenium,rhodium, palladium, platinum and iridium. Of these, ruthenium, rhodium,palladium and platinum are preferable, and palladium is more preferable.

There are usable metal complexes having any of a variety of structures,of which a metal complex having so called a low valency is suitable. Inparticular, a metal complex having zero valency is preferable whichcontains a tertiary phosphine or a tertiary phosphite as a ligand.Moreover it is also preferable to use a precursory complex which caneasily be converted in the reaction system, into palladium complexhaving zero valency. It is also a preferable embodiment to adopt amethod which comprises mixing in the reaction system, a metal complexwhich does not contain a tertiary phosphine or a tertiary phosphite as aligand and a tertiary phosphine or a tertiary phosphite, thus generatinga palladium complex having zero valency which contains the tertiaryphosphine or tertiary phosphite as a ligand, and using the aforesaidpalladium complex as such. Examples of the ligand that exhibits anadvantageous performance in any of the above-mentioned methods include avariety of tertiary phosphines and tertiary phosphites. Preferablyusable ligands are exemplified by triphenylphosphine,diphenylmethylphosphine, phenyldimethyl phosphine, trimethylphosphine,triethylphosphine, diphenylcyclohexylphosphine,phenyldicyclohexylphosphine, 1,4-bis(diphenylphosphino)butane,trimethylphosphite and triphenylphosphite. The metal complex which doesnot contain a tertiary phosphine or a tertiary phosphite as a ligand andwhich is used in combination with any of them is exemplified by, but isnot limited to bis(benzylideneacetone) palladium and palladium acetate.Preferably usable complex of a phosphine or phosphite is exemplified bydimethylbis(triphenylphosphine)palladium,dimethylbis(diphenylmethylphosphine) palladium {abbreviated to cis-PdMe₂(P.ph₂.Me)₂}, dimethylbis(triethylphosphine)palladium,(ethylene)bis(triphenylphosphine) palladium andtetrakis(triphenylphosphine) palladium. In addition, there may be usedas such a complex having two valencies such as palladium which has beentreated with a reducing agent such as butyllithium. More preferableexample thereof is dimethylbis(diphenylmethylphosphine) palladium{abbreviated to cis-PdMe₂(P.ph₂.Me)₂}.

Examples of the above-mentioned radical generating agent include diacylperoxides such as acetyl peroxide, isobutyl peroxide, octanoyl peroxideand decanoyl peroxide; diisopropyl peroxydicarbonate and di-2-ethylhexylperoxydicarbonate; peroxy esters such as tert-butyl peroxyisobutyrate,tert-butyl perpivalate and 1,1,3,3-tetrabutyl peroxy-2-ethylhexanoate;and azobis such as 2,2′-azobis(2-methylpropylnitrile), 2,2′-azobis(2,4-dimethylvaleronitrile) and dimethyl-2,2′-azobis(2-methylpropionate.Preferable example thereof is 1,1,3,3-tetrabutylperoxy-2-ethylhexanoate.

Optimum reaction time, which is different depending on starting rawspecies and presence/absence of a catalyst, is 1 to 16 hours. A reactiontime of less than one hour leads to lowered production efficiency of aphosphorus-containing dicarboxylic acid.

The novel process for producing the above-describedphosphorus-containing dicarboxylic acid makes it possible to refine boththe product and starting raw material only by means of filtration afterthe reaction through the use of acetonitrile or methoxypropyl acetateeach having high general-purpose properties, and easily refine theresidual acetonitrile or methoxypropyl acetate as the solvent by meansof vacuum removal in the case of completely removing the solvent,whereby highly pure objective product is obtained.

Further, the process for producing the above-describedphosphorus-containing dicarboxylic acid is capable of proceeding withthe reaction at a low temperature as compared with the prior arts,whereby white phosphorus-containing dicarboxylic acid is obtainable inhigh yield.

Furthermore, the process for producing the above-describedphosphorus-containing dicarboxylic acid enables to suppressuncontrollable sudden temperature rise by proceeding with the reactionat a low temperature as compared with the prior arts, proceed with thereaction under reflux, since the boiling points of the acetonitrile andmethoxypropyl acetate are about 80° C. and 146° C., respectively.

The phosphorus-containing dicarboxylic acid derivative according to thepresent invention, when being heated or irradiated with activationenergy beam such as ultraviolet ray or electron beam, causes eliminationof a vinyl ether compound, vinyl thioether compound, divinyl ethercompound or divinyl thioether compound, thus enabling to regenerate theoriginal carboxylic groups (deblocking). An acid catalyst acceleratesthis regeneration reaction of the free acid. Examples of the acidcatalyst include protonic acid such as halogenocarboxylic acid, sulfonicacid, monoester of sulfuric acid, monoester of phosphoric acid, diesterof phosphoric acid, polyphosphoric acid ester, monoester of boric acidand diester of boric acid; and Lewis acid such as boron fluoride (BF₃),ferric chloride (FeCl₃), stannic chloride (SnCl₄), aluminum chloride(AlCl₃) and zinc chloride (ZnCl₂). There is also available as aphotoacid catalyst, Adeka Optomer Sp series (trade name; available fromAsahi Denka Industrial Co., Ltd.).

The phosphorus-containing carboxylic acid derivative to be obtained inthe aforesaid manner is utilized also as a curing agent for varioussynthetic resins each having a reactive functional group. The carboxylicgroup regenerated after deblocking rapidly reacts with a reactivefunctional group of a synthetic resin, whereby flame-retardative curedsynthetic resin is easily obtained. Examples of the reactive functionalgroups include epoxy group, silanol group, alkoxysilane group, hydroxylgroup, amino group, imino group, isocyanate group, blocked isocyanategroup, cyclocarbonate group, vinyl ether group, vinyl thioether group,aminomethylol group, alkylatd aminomethylol group, acetal group andketal group. Examples of the synthetic resin having such reactivefunctional group include epoxy group-containing compound such as epoxyresin of bisphenol A type, epoxy resin of bisphenol F type, epoxy resinof cresol novolak type, epoxy group-modified silicone resin, epoxy resinof phenol novolak type, alicyclic epoxy resin, homopolymer and copolymerof glycidyl(meth)acrylate or 3,4-epoxycyclohexylmethyl(meth)acrylate,polyglycidyl compound which is obtained by the reaction betweenpolycarboxylic acid or polyol and epichlorohydrin; compounds such as thecondensation product of the compound represented by the followingformula (28):(R²⁰)_(n)Si(OR²¹)_(4-n)  (28)wherein R²⁰ and R²¹ are each an alkyl group having 1 to 18 carbon atomsor an aryl group, and n is 0, 1 or 2, homopolymer and copolymer ofα,β-unsaturated silane compounds such asacryloyloxypropyltrimethoxysilane, methacryloyloxypropyltrimethoxysilaneand silane compounds such as acryloyloxypropyltrimethoxysilane,methacryloyloxypropyltrimethoxysilane and compounds each containingsilanol group or alkoxysilane group exemplified bymethacryloyloxypropyltri-n-buthoxysilane and a hydrolysis product of anyof the above-cited compounds; hydroxy group-containing compounds such asaliphatic polyols, phenols, polyalkyleneoxy glycols, homopolymer andcopolymer of an α,β-unsaturated compound such as2-hydroxyethyl(meth)acrylate and 2-hydroxypropyl(meth)acrylate and anadduct of any of these polyols with ε-caprolactone; aminogroup-containing compound such as aliphatic and aromatic diaminocompounds, polyamino compounds and polyamino compounds each beingobtained by reducing cyanoethylation reaction product of theabove-mentioned polyols; imino group-containing compounds such asaliphatic and aromatic polyimino compounds; isocyanate group-containingcompounds such as p-phenylene diisocyanate, biphenyldiisocyanate,tolylenediisocyanate, 3,3′-dimethyl-4,4′-biphenylenediisocyanate,1,4-tetramethylenediisocyanate, hexamethylenediisocyanate,2,2,4-trimethylhexane-1,6-diisocyanate, methylenebis(phenylisocyanate),lysinemethylesterdiisocyanate, bis(isocyanateethyl)fumarate,isophoronediisocyanate, methylcyclohexyldiisocyanate,2-isocyanateethyl-2,6-diisocyanate hexanoate, biuret thereof,isocyanurate thereof, an adduct compound of any of these isocyanateswith the above-mentioned polyols; blocked isocyanate group-containingcompounds such as a blocked product of any of the above-exemplifiedisocyanate group-containing compounds blocked with any of phenols,lactams, active methylenes, alcohols, acid amides, imides, amines,imidazoles, ureas, imines and oximes; cyclocarbonate group-containingcompounds such as homopolymer and copolymer of3-(meth)acryloyloxypropylene carbonate, polyvalent cyclocarbonategroup-containing compounds obtained by the reaction between any of theepoxy group-containing compounds and carbon dioxide; compoundscontaining a vinyl ether group or vinyl thioether ether group such aspolyvalent vinyl ether compounds obtained by the reaction between theaforesaid polyvalent hydroxyl group-containing compounds and halogenatedalkylvinyl ether, polyvinyl ether compounds obtained by the reactionbetween hydroxyalkylvinyl ether and polyvalent carboxyl group-containingcompound or the above-exemplified polyisocyanate compound, vinyl ethercompounds exemplified by the copolymer of vinyloxyalkyl(meth)acrylateand an α,β-unsaturated compound, and vinyl thioether compounds eachcorresponding to any of the foregoing; compounds containing anaminomethylol group or alkylated aminomethylol group such asmelamine-formaldehyde resin, glycolyl-formaldehyde resin,urea-formaldehyde resin, homopolymer and copolymer of an α,β-unsaturatedcompound containing an aminomethylol group or alkylated aminomethylolgroup; and compounds containing an acetal group or ketal group such aspolyvalent ketones, polyvalent aldehyde compounds, polyvalent acetalcompounds obtained by the reaction between the foregoing polyvalentvinyl ether compound and an alcohol or oxoacid ester, condensationproduct between any of them and a polyol compound, homopolymer andcopolymer of an adduct of the vinyloxyalkyl(meth)acrylate with analcohol or an oxoacid ester.

The resin composition according to the present invention comprises asindispensable ingredients, a synthetic resin bearing in its molecule, atleast two reactive functional groups reactive with a carboxylic group,and the foregoing phosphorus-containing carboxylic acid derivative.Those which the synthetic resin possesses and which have already beendescribed on the curing agent exemplify the reactive functional groups.The synthetic resin bearing in is molecule, at least two reactivefunctional groups reactive with a carboxylic group is exemplified byepoxy resin. The synthetic resin, which bears at least two reactivefunctional groups, forms crosslinked structure for thephosphorus-containing carboxylic acid derivative. The above-mentionedresin composition may be blended at need, with a curing agent, filler,pigment, coloring agent, plasticizer, catalyst, solvent and the like.

In the resin composition, the content of the carboxylic group after thedeblocking of the phosphorus-containing carboxylic acid derivative ispreferably 0.1 to 5.0 equivalents based on one equivalent of thereactive functional groups reactive with a carboxylic group, morepreferably 0.2 to 3.0 equivalents. The content thereof, when being lessthan 0.1 equivalent, brings about markedly lowered phosphorusconcentration in a resin molded article, thereby deteriorating theworking effect on flame retardancy, coloring preventiveness and heatresistance, whereas the content thereof, when being more than 5.0equivalents, gives rise to a tendency to deteriorate the mechanicalproperties of the resin molded article.

The content of the phosphorus atoms in the resin composition ispreferably in the range of 0.1 to 15% by weight. The content thereof,when being less than 0.1% by weight, leads to failure in sufficientlyexhibiting the functions such as heat resistance and flame retardancy,whereas the content thereof, when being more than 15% by weight, bringsabout deterioration in the properties inherent to the synthetic resin.

The above-mentioned phosphorus-containing carboxylic acid derivative isused as effective ingredients for a flame retardant, coloring preventiveagent and heat resistance-imparting agent. In the case where thephosphorus-containing carboxylic acid derivative is used as a flameretardant, it is preferable that the content of the phosphorus atomscontained in the resin molded article (cured resin) produced by moldingthe resin composition be regulated to the range of 1.5 to 15% by weight.In the case, however, where an other flame retardant is used incombination, the content thereof even less than 1.5% by weight canexhibit the working effect. In the case where the phosphorus-containingcarboxylic acid derivative is used as a coloring preventive agent, it ispreferable that the content of the phosphorus atoms contained in theresin molded article be regulated to the range of 0.1 to 15% by weight.In the case where the phosphorus-containing carboxylic acid derivativeis used as a heat resistance-imparting agent, it is preferable that thecontent of the phosphorus atoms contained in the resin molded article beregulated to the range of 1 to 15% by weight. The content thereof, whenbeing less than each of the lower limits, unfavorably results inunrecognized improvement in flame retardancy, coloring preventivenessand heat resistance, whereas the content thereof, when being more than15% by weight in any case, unfavorably leads to unreasonably high waterabsorption of the resin molded article.

Subsequently, curing the resin composition and molding the same into apredetermined shape obtain a resin-molded article. A curing method usinga curing agent is usually adopted. The phosphorus-containing carboxylicacid derivative according to the present invention can function alone asa curing agent, but can be used in combination with another curingagent. Usable other curing agent is exemplified by any of thecustomarily used curing agents such as an acid anhydride, polyaminebased compound and phenol based compound, and a compound produced bymodifying a carboxylic acid with the compound bearing the grouprepresented by the foregoing formula (8). The amount of the other curingagent to be used is limited to preferably at most 120% by weight basedon the phosphorus-containing carboxylic acid derivative. When the amountthereof is 120% or more by weight, the content of the phosphorus atomsin the resin molded article is lowered, thereby sometimes causing afailure in obtaining the required flame retardancy.

According to the purpose of use, there is adopted as a method formolding the resin composition, cast molding method, injection moldingmethod, extrusion molding method, vacuum molding method and compressionmolding method that have hitherto been used for molding a syntheticresin.

The resin-molded article (cured resin) produced by molding the resincomposition becomes practical by adding the same to any of varioussynthetic resins. Examples of the synthetic resins to be added includeepoxy resin, phenolic resin, melamine resin and unsaturated polyesterresin.

The form of the resin-molded article may be any of fiber, nonwovenfabric, film and sheet. The resin composition may be impregnated into aninorganic or organic reinforcing material in the form of fiber, nonwovenfabric or woven fabric and thereafter cured and molded to obtain theresin-molded article.

Laminating such resin-molded article with a substrate can form alaminated sheet. Practical examples of the substrate include wovenfabric and nonwoven fabric each composed of inorganic fibers such asglass, organic fibers such as polyester, aramid, polyamide, polyacrylateor polyimide and natural fibers such as cotton and also include papers,etc. It is possible to integrate the resin composition with thesubstrate by applying the resin composition over the substrate orimmersing the substrate in the resin composition.

The amount of the resin composition to be used is preferably 30 to 80parts by mass expressed in terms of solid content in the resincomposition in parts by mass per 100 parts by mass totalizing said solidcontent and the substrate. In this case, solid content in the resincomposition consists of the resin bearing at least two reactivefunctional groups reactive with a carboxylic group,phosphorus-containing carboxylic acid derivative and the curing agent tobe blended on demand. The amount thereof to be used, when being lessthan 30 parts by mass, sometimes induces such defect as unevendistribution of the solid content amount to be impregnated into thesubstrate, thereby deteriorating the heat resistance of the objectivelaminated sheet and causing fluctuation of the electricalcharacteristics. On the contrary, the amount thereof to be used, whenbeing more than 80 parts by mass, sometimes brings about unreasonablylarge variation of the thickness of the objective laminated sheet.

Thereafter a prepreg is obtained by curing the resin composition bymeans of heating, light irradiation or combination of heating and lightirradiation. In the case where the resin composition contains a solvent,the solvent may be removed prior to curing the resin. The objectivelaminated sheet is obtained by superimposing a plurality of the prepregsobtained in such a manner, locating as necessary, metal foils overeither a surface or both surfaces thereof and then heat treating theprepregs. It is possible in the case of forming the laminated sheet tocombine the above-mentioned prepreg and a prepreg in which a resincomposition other than that of the present invention has beenimpregnated into a substrate.

A covered product is obtainable which has a covering layer or layersover either a surface or both surfaces of any of various substrates byapplying the resin composition according to the present invention overthe surface/s. The covered product is used usually after curing, but maybe used in a state of uncuring. Examples of the use in an uncured stateinclude a seal tape which is formed by covering the resin compositionover a sheet so that the covered surface constitutes a tacky adhesivesurface. Examples of the covered products (coated articles) includeelectronic products, structures, wooden products, metallic products,plastics products, rubber products, processed paper, ceramics productsand glass products and more specifically, electronic products,automobiles, metallic sheet such as steel sheets, two-wheeled vehicles,marine vessels and ships, railway rolling stocks, airplanes, furniture,musical instruments, electrical appliances, building materials,containers, office supplies, sporting goods and toys.

Coating methods for the resin composition according to the presentinvention is exemplified by conventionally used methods such as brushcoating, spray coating, immersion coating, flow coating and the like.

Further, a resin cast material is obtainable by casting the resincomposition into a casting mold and then curing the same. A generalcasting method is exemplified by vacuum casting method, namely a methodwhich comprises sufficiently uniformly heating and mixing in advance,the resin composition, mixing the composition by means of an agitator orthe like, vacuum casting the composition and curing the same by heatingor the like to obtain a cast product. The cast material thus obtained,when applied to covering or insulation for an electronic part orelectrical part, is made into a resin product imparted with flameretardancy.

In addition, the resin composition according to the present invention isusable as a resin sealing material for an electronic part and the like.In this case, the resin sealing material is usable in the form ofliquid, or by tablet having a dimension and mass matching with moldingconditions. As a method in which epoxy resin is used as the resinsealing material for sealing a device, a low-pressure transfer moldingmethod is most common, but injection molding method and compressionmolding method may also be used.

Examples of electronic parts obtainable by sealing a device with theresin sealing material include a device which is mounted to a carryingmember and necessary portion of which is sealed with epoxy resin,wherein the carrying member is exemplified by lead frame, already wiredtape carriers, wiring boards, glass, silicon, wafer and the like, andthe device is exemplified by active elements such as a semiconductorchip, transistor, diode and thruster; passive elements such as acapacitor, resistor and coil; a light-emitting diode (LED) and the like.

Further, examples of the electronic parts include general resin-sealedtype IC, which is produced by fixing a semiconductor device on a leadframe, connecting a terminal part of an element such as a bonding pad toa lead part by wire bonding or bump and thereafter, sealing theconnection by transfer molding or the like by the use of an epoxy resinmolded article for sealing; such as DIP (Dual Inline Packing), PLCC(Plastic Leaded Chip Carrier), QFP (Quad Flat Package), SOP (SmallOutline Package), SOJ (Small Outline J-lead Package), TQFP (Thin QuadFlat Package), etc.; TCP (Tape Carrier Package) in which a semiconductorthat is connected to a tape carrier by bump is sealed with the epoxyresin molded article for sealing; COB (Chip On Board) Module which isproduced by sealing, with the epoxy resin molded article for sealing, anactive element such as a semiconductor chip, transistor, diode andthyristor and/or passive element such as a capacitor, resistor and coil,each being connected onto wirings formed on a wiring board or glass bymeans of wire bonding, flip chip bonding, soldering or the like; hybridIC; multi-chip module; BGA (Ball Grid Array) which is produced bymounting an element to the surface of an organic substrate in which aterminal for connecting a wiring board is formed on the rear side,connecting the element to the wiring formed on the organic substrate bywire bonding or bump and thereafter sealing the device with the resincomposition; and CSP (Chip Size Package). Moreover the resin compositionaccording to the present invention is effectively usable for a printedcircuit board.

In addition, a covering material, an adhesive and the like are obtainedfrom the phosphorus-containing carboxylic acid derivative or a resincomposition containing the same. The covering material and adhesiveobtained therefrom can manifest excellent solubility in organicsolvents, favorable flame retardancy, heat resistance and the like onthe basis of the characteristics inherent in the phosphorus-containingcarboxylic acid derivative according to the present invention.

As described hereinbefore, the phosphorus-containing carboxylic acidderivative according to the present invention, in which the carboxylicgroups are modified (blocked) with the vinyl ether, vinyl thioether,divinyl ether or divinyl thioether, is lowered in polarity, and therebyis excellent in solubility in organic solvents, especially in non-polarorganic solvents and beside, in compatibility with a variety ofsynthetic resins. Besides, the phosphorus-containing carboxylic acidderivative according to the present invention has favorable stability,since even when being mixed with a resin bearing a group reactive with acarboxylic acid, curing reaction based on the carboxylic group does notproceed.

Moreover, the above-mentioned phosphorus-containing carboxylic acidderivative, which contains phosphorus atom as an essential component, isexcellent in self-fire-extinguishing properties and flame retardancy.Further, the foregoing phosphorus-containing carboxylic acid derivative,which is endowed with antioxidant action, is excellent in coloringprevention and besides, can exhibit excellent heat resistance, since ithas such properties as absorbing excess energy locally applied by heat,or light.

Furthermore, the phosphorus-containing carboxylic acid derivativeaccording to the present invention is easily producible in high yield byallowing the phosphorus-containing carboxylic acid bearing both acarboxylic group and phosphorus atoms to react with a vinyl ethercompound or vinyl thioether compound.

The above-mentioned resin composition is obtained from thephosphorus-containing carboxylic acid derivative according to thepresent invention and the synthetic resin bearing in its molecule, atleast two reactive functional groups reactive with a carboxylic group,and is capable of exerting the characteristics inherent in the aforesaidderivative. Likewise, a resin-molded article formed by curing the resincomposition is also capable of exerting the characteristics inherent inthe aforesaid resin.

In what follows, the embodiments of the present invention will bedescribed in more detail with reference to working examples, whichhowever shall never limit the present invention thereto insofar as itdoes not depart form the spirit and purport thereof.

In the following, the compounds to be used in the present invention willbe described.

(a) 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, the compoundrepresented by the foregoing formula (16) {available from Sanko Co.,Ltd. under the trade name “SANKO-HCA”}, hereinafter abbreviated to“HCA”.

(b) M-Acid {available from Sanko Co., Ltd.}, common name, which will bealso used as such in this specification, the compound represented byabove-mentioned formula (15).

(c) diethylhydrogen phosphite (hereinafter abbreviated to “DEHP”), thecompound represented by the following formula (c):

(d) diphenylhydrogen phosphite (hereinafter abbreviated to “DPHP”), thecompound represented by the following formula (d):

(e) 2-phosphonobutane-1,2,4-tricarboxylic acid (hereinafter abbreviatedto “PBTC”, available from Jouhoku Chemical Industrial Co., Ltd.), thecompound represented by the following formula (e):

In the following, explanations will be described about the measuringmethod and evaluation method used in the working examples of the presentinvention.

1. Measuring Conditions for ¹H-NMR

Type of instrument: 400 MHz type “Advance 400”, produced by Japan BulcarCo., Ltd.

Number of times of integration: 16 times

Solvent: CD₃OD, TMS standard in Reference Examples 1 to 7 and inComparative Reference Example 1 and CDCl₃, TMS standard in Examples 1 to10.

2. Measurement of Acid Equivalent

The acid equivalent was measured in accordance with JIS K 0070-3 (1992).

3. Measurement of Yield and Purity

The yield and purity were determined by liquid chromatography(hereinafter abbreviated to “LC”), followed by conversion.

Measuring Conditions for LC

Type of instrument: “SC-8010” produced by Tosoh Corporation.

Column: “Inertsil ODS-3” produced by GL Science Co., Ltd.

Elute: mixed liquid of methanol/propionic acid (4/1)

4. Measuring Conditions for IR

Type of instrument: “FT/IR-600” produced by Japan Spectroscopy Co., Ltd.

Cell: tablet method employing potassium bromide

Resolution: 4 cm⁻¹

Number of times of integration: 16 times

5. Measurement of Molecular Weight

The molecular weight was calculated from gel size permeationchromatography (hereinafter abbreviated to “GPC”)

Type of instrument: “SC-8010” produced by Tosoh Corporation.

Column: “SHODEX K-801” produced by Showa Denko Co., Ltd.

Elute: tetrahydrofuran (THF)

Detector: RI

6. Solubility Test

One part by weight of each of samples and 4 parts by weight of each ofsolvents were placed into a vial, and the resultant mixture was stirredat room temperature for one hour with the use a rotor. After thestirring, the solubility of the sample was visually observed.

7. Storage Stability Test

One part by weight of each of samples and one part by weight of epoxyresin of phenol/novolak type (“YDPN 638”, trade name; available fromToto Kasei Co., Ltd.) were placed into a vial and the resultant mixturewas stirred at room temperature for one hour with the use of a rotor,and after the stirring, it was allowed to stand at room temperature for30 days. Then a visual observation was made about an increase in theviscosity thereof.

8. Combustion Test

The combustion test was carried out in accordance with UL (UnderwriterLaboratories) 94 Thin Material Vertical Burning Test.

9. Measurement of Acid Value

The acid value was calculated by accurately weighing a sample, and bytitration with potassium hydroxide/ethanol solution having a knownconcentration.

10. Solvent Resistance Test

Solvent resistance was tested by rubbing a sample in 30 reciprocationtimes with kim wipe (trade name; available from Kresia Co., Ltd.)impregnated with acetone, and visually observing scratch.

11. Observation of Coloring

A sample film was heated in a hot air wind oven under the heatingconditions of 230° C. for 30 minutes, and the extent of coloring wasvisually observed.

12. Heat Resistance Test

A sample film was heated, and the temperature at which the weightthereof was decreased by 5% was regarded as thermal decompositiontemperature. The heat resistance was evaluated by the standard whetherthe thermal decomposition temperature is at least 330° C. or not.

REFERENCE EXAMPLE 1 Synthesis of M-Acid by the Use of Acetonirile as theSolvent

A four-neck flask equipped with a reflux condenser, a stirrer and athermometer was charged with 30.1 parts by weight of HCA, 19.9 parts byweight of itaconic acid and 50.0 parts by weight of acetonitrile, andthe resultant mixture was reacted with one another at 81° C. for 4 hoursunder stirring. When the reaction liquid thus formed was cooled to roomtemperature, white crystal was precipitated and accordingly separated byfiltration. When the white crystal thus obtained was dried with the useof a vacuum dryer under the conditions of 20 mmHg, 80° C. for one hour,there was obtained 44.7 g of a white crystal having a melting point inthe range of 191 to 198° C. and an acid value of 171 g/mol. Ameasurement was made of ¹H-NMR of the product with a result that peakswere confirmed at 7.27 to 8.15 ppm (m, H8), at 3.31 to 3.32 ppm (m, H1)and at 2.50 to 2.82 ppm (m, H2), and thus the structure of productrepresented by the foregoing formula (15) was confirmed.

Further, a measurement was made of the purity of the product. As aresult, the purity was 98.4% by weight, while containing 1.6% by weightof itaconic acid as an impurity. The yield thereof calculated on thebasis of the amount of charge was 88.0% by weight.

REFERENCE EXAMPLE 2 Synthesis of M-Acid by the Use of Acetonirile andPMAc as the Solvents

A four-neck flask equipped with a reflux condenser, a stirrer and athermometer was charged with 30.1 parts by weight of HCA, 19.9 parts byweight of itaconic acid, 20.0 parts by weight of acetonitrile and 30.0parts by weight of PMAc (methoxypropyl acetate), and the resultantmixture was reacted with one another at 110° C. for 4 hours understirring. When the reaction liquid thus formed was cooled to roomtemperature, white crystal was precipitated and accordingly separated byfiltration. When the white crystal thus obtained was dried with the useof a vacuum dryer under the conditions of 20 mmHg, 80° C. for one hour,there was obtained 46.6 g of a white crystal having a melting point inthe range of 196 to 198° C. and an acid value of 172 g/mol. Ameasurement was made of ¹H-NMR of the product with a result that peakswere confirmed at 7.27 to 8.15 ppm (m, H8), at 3.31 to 3.32 ppm (m, H1)and at 2.50 to 2.82 ppm (m, H2), and thus the structure of productrepresented by the foregoing formula (15) was confirmed.

Further, a measurement was made of the purity of the product. As aresult, the purity was 99.4% by weight, while containing 0.6% by weightof itaconic acid as an impurity. The yield thereof calculated on thebasis of the amount of charge was 92.6% by weight.

REFERENCE EXAMPLE 3 Synthesis of M-Acid by the Use of PMAc as theSolvents

A four-neck flask equipped with a reflux condenser, a stirrer and athermometer was charged with 30.1 parts by weight of HCA, 19.9 parts byweight of itaconic acid and 30.0 parts by weight of PMAc (methoxypropylacetate), and the resultant mixture was reacted with one another at 122°C. for 2 hours under stirring. At that time, white crystal wasprecipitated. Further stirring was continued for one hour, the reactionliquid thus formed was cooled to room temperature, and the white crystalwas separated by filtration. The white crystal thus obtained in anamount of 20 parts by weight was dried with the use of a vacuum dryerunder the conditions of 20 mmHg, 80° C. for one hour, there was obtained48.4 g of a white crystal having a melting point in the range of 196 to198° C. and an acid value of 172 g/mol. A measurement was made of ¹H-NMRof the product with a result that peaks were confirmed at 7.27 to 8.15ppm (m, H8), at 3.31 to 3.32 ppm (m, H1) and at 2.50 to 2.82 ppm (m,H2), and thus the structure of product represented by the foregoingformula (15) was confirmed.

Further, a measurement was made of the purity of the product. As aresult, the purity was 99.6% by weight, while containing 0.2% by weightof itaconic acid as an impurity. The yield thereof calculated on thebasis of the amount of charge was 96.4% by weight.

REFERENCE EXAMPLE 4 Synthesis of M-Acid by the Use of Acetonitrile asthe Solvent and DBU as the Catalyst

A four-neck flask equipped with a reflux condenser, a stirrer and athermometer was charged with 30.1 parts by weight of HCA, 19.9 parts byweight of itaconic acid, 50.0 parts by weight of acetonitrile and 0.5part by weight of DBU, and the resultant mixture was reacted with oneanother at 81° C. for 4 hours under stirring. When the reaction liquidthus formed was cooled to room temperature, white crystal wasprecipitated and accordingly separated by filtration. When the whitecrystal thus obtained was dried with the use of a vacuum dryer under theconditions of 20 mmHg, 80° C. for one hour, there was obtained 47.4 g ofa white crystal having a melting point in the range of 193 to 198° C.and an acid value of 170 g/mol. A measurement was made of ¹H-NMR of theproduct with a result that peaks were confirmed at 7.27 to 8.15 ppm (m,H8), at 3.31 to 3.32 ppm (m, H1) and at 2.50 to 2.82 ppm (m, H2), andthus the structure of product represented by the foregoing formula (15)was confirmed.

Further, a measurement was made of the purity of the product. As aresult, the purity was 98.7% by weight, while containing 1.2% by weightof itaconic acid as an impurity. The yield thereof calculated on thebasis of the amount of charge was 93.6% by weight.

REFERENCE EXAMPLE 5 Synthesis of Adduct of DEHP with Itaconic Acid bythe Use of PMAc as the Solvent

A four-neck flask equipped with a reflux condenser, a stirrer and athermometer was charged with 36.0 parts by weight of DEHP, 34.0 parts byweight of itaconic acid and 30.0 parts by weight of PMAc (methoxypropylacetate), and the resultant mixture was reacted with one another at 120°C. for 6 hours under stirring. When the PMAc was distilled away underreduced pressure (20 mmHg) at the temperature of 80° C. for one hour,70.3 parts by weight of yellow liquid was obtained. A measurement wasmade of ¹H-NMR of the product with a result that peaks were confirmed at4.05 to 4.20 ppm (m, H6), at 3.30 to 3.35 ppm (m, H2), at 2.06 to 2.12ppm (m, H1) and 1.17 to 1.34 (m, H6), and thus, it was confirmed thatthe structure of the product was represented by the following formula(f):

Further, a measurement was made of the purity of the product. As aresult, the purity was 97.6% by weight, while containing PMAc, DEHP anditaconic acid each as trace impurity. The yield thereof calculated onthe basis of the amount of charge was 98.0% by weight. Hereinafter, theresultant phosphorus-containing carboxylic acid compound is referred toas DEHP-Ita A.

REFERENCE EXAMPLE 6 Synthesis of Adduct of DEHP with Maleic Acid by theUse of Acetonitrile as the Solvent

A four-neck flask equipped with a reflux condenser, a stirrer and athermometer was charged with 38.0 parts by weight of DEHP, 32.0 parts byweight of maleic acid and 30.0 parts by weight of acetonitrile, and theresultant mixture was reacted with one another in an autoclave at 110°C. for 4 hours under stirring. When the PMAc was distilled away underreduced pressure (20 mmHg) at the temperature of 100° C. for one hour,69.4 parts by weight of yellow liquid was obtained. A measurement wasmade of ¹H-NMR of the product with a result that peaks were confirmed at4.12 to 4.22 ppm (m, H4), at 3.28 to 3.31 ppm (m, H2), at 2.06 to 2.18ppm (m, H1) and 1.10 to 1.36 (m, H6), and thus, it was confirmed thatthe structure of the product was represented by the following formula(g):

Further, a measurement was made of the purity of the product. As aresult, the purity was 96.5% by weight, while containing PMAc, DEHP anditaconic acid each as trace impurity. The yield thereof calculated onthe basis of the amount of charge was 69.7% by weight.

Hereinafter, the resultant phosphorus-containing carboxylic acidcompound is referred to as DEHP-Mal A.

REFERENCE EXAMPLE 7 Synthesis of Adduct of DPHP with Itaconic Acid bythe Use of PMAc as the Solvent

A four-neck flask equipped with a reflux condenser, a stirrer and athermometer was charged with 45.0 parts by weight of DPHE, 25.0 parts byweight of itaconic acid and 30.0 parts by weight of PMAc (methoxypropylacetate), and the resultant mixture was reacted with one another at 120°C. for 6 hours under stirring. When the PMAc was distilled away underreduced pressure (20 mmHg) at the temperature of 100° C. for one hour,69.5 parts by weight of yellow liquid was obtained. A measurement wasmade of ¹H-NMR of the product with a result that peaks were confirmed at7.15 to 7.65 ppm (m, H10), at 4.00 to 4.09 ppm (m, H2), at 3.32 to 3.33ppm (m, H1) and at 2.04 to 2.05 (m, H2), and thus, it was confirmed thatthe structure of the product was represented by the following formula(h):

Further, a measurement was made of the purity of the product. As aresult, the purity was 98.5% by weight, while containing PMAc, DEHP anditaconic acid each as trace impurity. The yield thereof calculated onthe basis of the amount of charge was 97.8% by weight.

Hereinafter, the resultant phosphorus-containing carboxylic acidcompound is referred to as DPHP-Ita A.

COMPARATIVE REFERENCE EXAMPLE 1 Synthesis of M-Acid by the Use ofPropionic Acid as the Solvent

A four-neck flask equipped with a reflux condenser, a stirrer and athermometer was charged with 30.1 parts by weight of HCA, 19.9 parts byweight of itaconic acid and 50.0 parts by weight of propionic acid, andthe resultant mixture was reacted with one another at 140° C. for 8hours under stirring. During the course of the reaction, temperaturecontrol was difficult because of vigorous refluxing. When the reactionliquid thus formed was cooled to room temperature under stirring for 12hours, white crystal was precipitated and accordingly separated byfiltration. The white crystal thus obtained was dried with the use of avacuum dryer under the conditions of 20 mmHg, 80° C. for one hour, butremoval of propionic acid odor was impossible. As a result, there wasobtained 46.5 g of a white crystal having a melting point in the rangeof 193 to 196° C. and an acid value of 167 g/mol. A measurement was madeof ¹H-NMR of the product with a result that peaks were confirmed at 7.27to 8.15 ppm (m, H8), at 3.31 to 3.32 ppm (m, H1) and at 2.50 to 2.82 ppm(m, H2), and thus the structure of product represented by the foregoingformula (15) was confirmed.

Further, a measurement was made of the purity of the product. As aresult, the purity was 98.7% by weight, while containing 0.5% by weightof itaconic acid and 0.4% by weight of propionic acid each as animpurity. The yield thereof calculated on the basis of the amount ofcharge was 95.2% by weight.

The white crystal thus obtained had strong odor originating frompropionic acid. In view of the above, 10 parts by weight of the whitecrystal was suspended in 100 parts by weight of water, and the resultantsuspension was filtered. The operation of washing with 100 parts byweight of water was repeated 5 times, but removal of irritating odor ofpropionic acid remained impossible.

COMPARATIVE REFERENCE EXAMPLE 2 Synthesis of M-Acid by the Use of Wateras the Solvent

A four-neck flask equipped with a reflux condenser, a stirrer and athermometer was charged with 30.1 parts by weight of HCA, 19.9 parts byweight of itaconic acid and 50.0 parts by weight of water, and theresultant mixture was stirred at 100° C. for one hour. During thestirring, the solution turned into powder without proceeding of anyreaction.

COMPARATIVE REFERENCE EXAMPLE 3 Synthesis of M-Acid by the Use ofIsopropanol as the Solvent

A four-neck flask equipped with a reflux condenser, a stirrer and athermometer was charged with 30.1 parts by weight of HCA, 19.9 parts byweight of itaconic acid and 50.0 parts by weight of isopropanol, and theresultant mixture was reacted at 140° C. for 8 hours under stirring.After the completion of the reaction, the reaction liquid thus formedwas cooled to room temperature, while stirring for 12 hours, but nosolid was precipitated. Then, the reaction liquid was analyzed, but noM-Acid was detected.

COMPARATIVE REFERENCE EXAMPLE 4 Synthesis of M-Acid by the Use of MethylIsobutyl Ketone as the Solvent

A four-neck flask equipped with a reflux condenser, a stirrer and athermometer was charged with 30.1 parts by weight of HCA, 19.9 parts byweight of itaconic acid and 50.0 parts by weight of methyl isobutylketone, and the resultant mixture was reacted at 140° C. for 8 hoursunder stirring. After the completion of the reaction, the reactionliquid thus formed was cooled to room temperature, while stirring for 12hours, but no solid was precipitated. Then, the reaction liquid wasanalyzed, but no M-Acid was detected.

COMPARATIVE REFERENCE EXAMPLE 5 Synthesis of M-Acid by the Use ofCyclohexanone as the Solvent

A four-neck flask equipped with a reflux condenser, a stirrer and athermometer was charged with 30.1 parts by weight of HCA, 19.9 parts byweight of itaconic acid and 50.0 parts by weight of cyclohexanone, andthe resultant mixture was reacted at 140° C. for 8 hours under stirring.After the completion of the reaction, the reaction liquid thus formedwas cooled to room temperature, while stirring for 12 hours, but nosolid was precipitated. Then, the reaction liquid was analyzed, but noM-Acid was detected.

COMPARATIVE REFERENCE EXAMPLE 6 Synthesis of M-Acid by the Use of Xyleneas the Solvent

A four-neck flask equipped with a reflux condenser, a stirrer and athermometer was charged with 30.1 parts by weight of HCA, 19.9 parts byweight of itaconic acid and 50.0 parts by weight of xylene, and theresultant mixture was reacted at 140° C. for 8 hours under stirring.After the completion of the reaction, the reaction liquid thus formedwas cooled to room temperature, while stirring for 12 hours, but nosolid was precipitated. Then, the reaction liquid was analyzed, but noM-Acid was detected.

EXAMPLE 1 Phosphorus-Containing Carboxylic Acid Derivative Produced byModifying M-Acid with N-Propylvinyl Ether)

A four-neck flask equipped with a reflux condenser, a stirrer and athermometer was charged with 53.4 parts by weight of M-Acid which hadbeen obtained in the Reference Example 3, 31.9 parts by weight ofn-propylvinyl ether, 14.7 parts by weight of 2-butanone and 0.05 part byweight of AP-8 (phosphoric acid catalyst, available from by DaihachiChemical Industrial Co., Ltd.). The resultant mixture was stirred underthe conditions of 85° C. for 3 hours. The reactivity which wascalculated from the measured acid value was 99.3%. Then unreactedn-propylvinyl ether and unreacted 2-butanone were removed with the useof an evaporator under the conditions of 20 mmHg and 50° C. (the acidvalue after the vacuum concentration being 8.32 mg KOH/g).

The product thus obtained was colorless transparent highly viscousliquid. The infrared absorption spectrum thereof is shown as FIG. 1, andthe ¹H-NMR spectrum thereof is shown as FIG. 2.

The facts that the acid value of the product was remarkably low ascompared with that of the M-acid, and that any absorption assigned tothe carboxylic group was not confirmed from the infrared absorptionspectrum have rendered it possible to confirm that the carboxylic groupof the M-acid was modified with the n-propylvinyl ether. That is to say,the objective phosphorus-containing carboxylic acid derivative has thestructure represented by the following formula (i):

The objective phosphorus-containing carboxylic acid derivative had inits one molecule, two functional groups represented by the foregoingformula (2) and had phosphorus atom content of 5.98% by weight. In thefollowing, the phosphorus-containing carboxylic acid derivative thusobtained is referred to as Block acid A. The solubility test and thestorage stability test were carried out for the Block acid A. Theresults are shown in Table 1.

EXAMPLE 2 Phosphorus-Containing Carboxylic Acid Derivative Produced byModifying M-Acid with Tert-Butylvinyl Ether

A four-neck flask equipped with a reflux condenser, a stirrer and athermometer was charged with 25.4 parts by weight of M-Acid which hadbeen obtained in the foregoing Reference Example 3, 17.6 parts by weightof tert-butylvinyl ether, 7.1 parts by weight of 2-butanone and 0.025part by weight of AP-8 (phosphoric acid catalyst, available fromDaihachi Chemical Industrial Co., Ltd.). The resultant mixture wasstirred under the conditions of 85° C. for 2 hours. The reactivity whichwas calculated from the measured acid value was 99.1%. Then unreactedtert-butylvinyl ether and unreacted 2-butanone were removed with the useof an evaporator under the conditions of 20 mmHg and 50° C. (the acidvalue after the vacuum concentration being 9.61 mg KOH/g). The productthus obtained was light yellow transparent highly viscous liquid. Theinfrared absorption spectrum thereof is shown as FIG. 3. The facts thatthe acid value of the product was remarkably low as compared with thatof the M-acid, and that any absorption assigned to the carboxylic groupwas not confirmed from the infrared absorption spectrum have rendered itpossible to confirm that the carboxylic group of the M-Acid was modifiedwith the tert-butylvinyl ether. That is to say, the objectivephosphorus-containing carboxylic acid derivative has the structurerepresented by the following formula (j):

The objective phosphorus-containing carboxylic acid derivative had inits one molecule, two functional groups represented by the foregoingformula (2) and had phosphorus atom content of 5.67% by weight.

In the following, the phosphorus-containing carboxylic acid derivativethus obtained is referred to as Block acid B. In the same manner as inExample 1, the solubility test and the storage stability test werecarried out for the Block acid B. The results are shown in Table 1.

EXAMPLE 3 Phosphorus-Containing Carboxylic Acid Derivative Produced byModifying M-Acid with Ethylhexylvinyl Ether

A four-neck flask equipped with a reflux condenser, a stirrer and athermometer was charged with 21.0 parts by weight of M-Acid which hadbeen obtained in the foregoing Reference Example 3, 22.8 parts by weightof ethylhexylvinyl ether, 6.2 parts by weight of 2-butanone and 0.025part by weight of AP-8 (phosphoric acid catalyst, available fromDaihachi Chemical Industrial Co., Ltd.). The resultant mixture wasstirred under the conditions of 120° C. for 2 hours. The reactivitywhich was calculated from the measured acid value was 99.6%. Thenunreacted ethylhexylvinyl ether and unreacted 2-butanone were removedwith the use of an evaporator under the conditions of 20 mmHg and 50° C.(the acid value after the vacuum concentration being 4.47 mg KOH/g.)

The product thus obtained was light yellow transparent highly viscousliquid. The infrared absorption spectrum thereof is shown as FIG. 4. Thefacts that the acid value of the product was remarkably low as comparedwith that of the M-Acid, and that any absorption assigned to thecarboxylic group was not confirmed from the infrared absorption spectrumhave rendered it possible to confirm that the carboxylic group of theM-Acid was modified with the ethylhexylvinyl ether. That is to say, theobjective phosphorus-containing carboxylic acid derivative has thestructure represented by the following formula (k):

The objective phosphorus-containing carboxylic acid derivative had inits one molecule, two functional groups represented by the foregoingformula (2) and had phosphorus atom content of 4.71% by weight.

In the following, the phosphorus-containing carboxylic acid derivativethus obtained is referred to as Block acid C. In the same manner as inExample 1, the solubility test and the storage stability test werecarried out for the Block acid C. The results are shown in Table 1.

EXAMPLE 4 Phosphorus-Containing Carboxylic Acid Derivative Produced byModifying M-Acid with Isobutylvinyl Ether

A four-neck flask equipped with a reflux condenser, a stirrer and athermometer was charged with 25.4 parts by weight of M-acid which hadbeen obtained in the foregoing Reference Example 3, 17.6 parts by weightof isobutylvinyl ether, 7.1 parts by weight of 2-butanone and 0.025 partby weight of AP-8 (phosphoric acid catalyst, available from DaihachiChemical Industrial Co., Ltd.). The resultant mixture was stirred underthe conditions of 100° C. for 4 hours. The reactivity which wascalculated from the measured acid value was 99.1%. Then unreactedisobutylvinyl ether and unreacted 2-butanone were removed with the useof an evaporator under the conditions of 20 mmHg and 50° C. (the acidvalue after the vacuum concentration being 6.73 mg KOH/g). The productthus obtained was reddish yellow transparent highly viscous liquid. Theinfrared absorption spectrum thereof is shown as FIG. 5. The facts thatthe acid value of the product was remarkably low as compared with thatof the M-Acid, and that any absorption assigned to the carboxylic groupwas not confirmed from the infrared absorption spectrum have rendered itpossible to confirm that the carboxylic group of the M-Acid was modifiedwith the isobutylvinyl ether. That is to say, the objectivephosphorus-containing carboxylic acid derivative has the structurerepresented by the following formula (1):

The objective phosphorus-containing carboxylic acid derivative had inits one molecule, two functional groups represented by the foregoingformula (2) and had phosphorus atom content of 4.71% by weight.

In the following, the phosphorus-containing carboxylic acid derivativethus obtained is referred to as Block acid D. In the same manner as inExample 1, the solubility test and the storage stability test werecarried out for the Block acid D. The results are shown in Table 1.

EXAMPLE 5 Phosphorus-Containing Carboxylic Acid Derivative Produced byModifying M-Acid with Cyclohexyldimethanoldivinyl Ether

A four-neck flask equipped with a reflux condenser, a stirrer and athermometer was charged with 31.3 parts by weight of M-acid which hadbeen obtained in the foregoing Reference Example 3, 18.7 parts by weightof cyclohexyldimethanoldivinyl ether (CHDVE) and 50 parts by weight ofmethoxypropyl acetate (PMAc). The resultant mixture was stirred underthe conditions of 100° C. for 3 hours. The reactivity which wascalculated from the measured acid value was 98.3%. Then unreacted CHDVEand unreacted PMAc were removed with the use of an evaporator under theconditions of 20 mmHg and 50° C.

The product thus obtained was light yellow transparent highly viscousliquid. The infrared absorption spectrum thereof is shown as FIG. 6, andthe ¹H-NMR spectrum thereof is shown as FIG. 7. Further the molecularweight thereof was measured in accordance with the foregoing GPCprocedure. As a result, the weight-average molecular weight (Mw) wasabout 12,000, from which the average degree of polymerization “n” wascalculated as being 22.

The facts that the acid value of the product was remarkably low ascompared with that of the M-Acid, and that any absorption assigned tothe carboxylic group was not confirmed from the infrared absorptionspectrum have rendered it possible to confirm that the carboxylic groupof the M-acid was modified with the CHDVE. Moreover, it can be seen fromthe increased molecular weight that polymerization reaction took place.That is to say, the objective phosphorus-containing carboxylic acidderivative has the structure represented by the following formula (m):

The objective phosphorus-containing carboxylic acid derivative had inits one molecule, 22 functional groups represented by the foregoingformula (3) and had phosphorus atom content of 5.6% by weight.

In the following, the phosphorus-containing carboxylic acid derivativethus obtained is referred to as Block acid E. In the same manner as inExample 1, the solubility test and the storage stability test werecarried out for the Block acid E. The results are shown in Table 1.

EXAMPLE 6 Phosphorus-Containing Carboxylic Acid Derivative Produced byModifying M-Acid with 1,4-Butanedioldivinyl Ether

A four-neck flask equipped with a reflux condenser, a stirrer and athermometer was charged with 34.9 parts by weight of M-Acid which hadbeen obtained in the foregoing Reference Example 3, 15.1 parts by weightof 1,4-butanedioldivinyl ether (1,4-BDVE) and 50 parts by weight ofmethoxypropyl acetate (PMAc). The resultant mixture was stirred underthe conditions of 100° C. for 3 hours. The reactivity which wascalculated from the measured acid value was 98.6%. Then unreacted1,4-BDVE and unreacted PMAc were removed with the use of an evaporatorunder the conditions of 20 mmHg and 50° C.

The product thus obtained was light yellow transparent highly viscousliquid. The infrared absorption spectrum thereof is shown as FIG. 8, andthe ¹H-NMR spectrum thereof is shown as FIG. 9. Further the molecularweight thereof was measured in accordance with the foregoing GPCprocedure. As a result, the weight-average molecular weight (Mw) wasabout 8,000, from which the average degree of polymerization “n” wascalculated as being 16.

The facts that the acid value of the product was remarkably low ascompared with that of the M-Acid, and that any absorption assigned tothe carboxylic group was not confirmed from the infrared absorptionspectrum have rendered it possible to confirm that the carboxylic-groupof the M-Acid was modified with the CHDVE. Moreover, it can be seen fromthe increased molecular weight that polymerization reaction took place.That is to say, the objective phosphorus-containing carboxylic acidderivative has the structure represented by the following formula (n):

The objective phosphorus-containing carboxylic acid derivative had inits one molecule, 16 functional groups on an average represented by theforegoing formula (3) and had phosphorus atom content of 6.3% by weight.

In the following, the phosphorus-containing carboxylic acid derivativethus obtained is referred to as Block acid F. In the same manner as inExample 1, the solubility test and the storage stability test werecarried out for the Block acid F. The results are shown in Table 1.

EXAMPLE 7 Phosphorus-Containing Carboxylic Acid Derivative Produced byModifying M-Acid with Triethylene Glycol Divinyl Ether

A four-neck flask equipped with a reflux condenser, a stirrer and athermometer was charged with 30.9 parts by weight of M-acid which hadbeen obtained in the foregoing Reference Example 3, 19.1 parts by weightof triethylene glycol divinyl ether (TEGDVE) and 50 parts by weight ofmethoxypropyl acetate (PMAc). The resultant mixture was stirred underthe conditions of 100° C. for 3 hours. The reactivity which wascalculated from the measured acid value was 99.1%. Then unreacted TEGDVEand unreacted PMAc were removed with the use of an evaporator under theconditions of 20 mmHg and 50° C.

The product thus obtained was light yellow transparent highly viscousliquid. The infrared absorption spectrum thereof is shown as FIG. 10,and the ¹H-NMR spectrum thereof is shown as FIG. 11. Further themolecular weight thereof was measured in accordance with the foregoingGPC procedure. As a result, the weight-average molecular weight (Mw) wasabout 11,000, from which the average degree of polymerization “n” wascalculated as being 20.

The facts that the acid value of the product was remarkably low ascompared with that of the M-Acid, and that any absorption assigned tothe carboxylic group was not confirmed from the infrared absorptionspectrum have rendered it possible to confirm that the carboxylic groupof the M-Acid was modified with the TEGDVE. Moreover, it can be seenfrom the increased molecular weight that polymerization reaction tookplace. That is to say, the objective phosphorus-containing carboxylicacid derivative has the structure represented by the following formula(o):

The objective phosphorus-containing carboxylic acid derivative had inits one molecule, 20 functional groups on an average represented by theforegoing formula (3) and had phosphorus atom content of 5.5% by weight.

In the following, the phosphorus-containing carboxylic acid derivativethus obtained is referred to as Block acid G. In the same manner as inExample 1, the solubility test and the storage stability test carriedout for the Block acid G. The results are shown in Table 1.

EXAMPLE 8 Phosphorus-Containing Carboxylic Acid Derivative Produced byModifying PBTC with N-Propylvinyl Ether

A four-neck flask equipped with a reflux condenser, a stirrer and athermometer was charged with 46.6 parts by weight of PBTC and 53.4 partsby weight of n-propylvinyl ether. The resultant mixture was stirredunder the conditions of 53° C. for 4 hours. The reactivity which wascalculated from the measured acid value was 97.3%. Then unreactedn-propylvinyl ether was removed with the use of an evaporator under theconditions of 20 mmHg and 50° C. (the acid value after the vacuumconcentration being 226 mg KOH/g).

The product thus obtained was yellow transparent highly viscous liquid.The infrared absorption spectrum thereof is shown as FIG. 12.

The facts that the acid value of the product was remarkably low ascompared with that of the PBTC before the reaction, and that anyabsorption assigned to the carboxylic group was not confirmed from theinfrared absorption spectrum have rendered it possible to confirm thatthe carboxylic group of the PBTC was modified with the n-propylvinylether. That is to say, the objective phosphorus-containing carboxylicacid derivative has the structure represented by the following formula(p):

The objective phosphorus-containing carboxylic acid derivative had inits one molecule, 3 functional groups represented by the foregoingformula (2) and had phosphorus atom content of 6.45% by weight.

In the following, the phosphorus-containing carboxylic acid derivativethus obtained is referred to as Block acid H. In the same manner as inExample 1, the solubility test and the storage stability test werecarried out for the Block acid H. The results are shown in Table 1.

EXAMPLE 9 Phosphorus-Containing Carboxylic Acid Derivative Produced byModifying DEHP-ItaA with N-Propylvinyl Ether

A four-neck flask equipped with a reflux condenser, a stirrer and athermometer was charged with 56.5 parts by weight of DEHP-ItaA which hadbeen obtained in the Reference Example 5, and 43.5 parts by weight ofn-propylvinyl ether. The resultant mixture was stirred under theconditions of 10° C. for 6 hours. The reactivity which was calculatedfrom the measured acid value was 97.2%. Then unreacted n-propylvinylether was removed with the use of an evaporator under the conditions of20 mmHg and 50° C. (the acid value after the vacuum concentration being11.8 mg KOH/g).

The product thus obtained was brown transparent highly viscous liquid.The infrared absorption spectrum thereof is shown as FIG. 13.

The facts that the acid value of the product was remarkably low ascompared with that of the DEHP-ItaA before the reaction, and that anyabsorption assigned to the carboxylic group was not confirmed from theinfrared absorption spectrum have rendered it possible to confirm thatthe carboxylic group of the DEHP-ItaA was modified with then-propylvinyl ether. That is to say, the objective phosphorus-containingcarboxylic acid derivative has the structure represented by thefollowing formula (q):

The objective phosphorus-containing carboxylic acid derivative had inits one molecule, 2 functional groups represented by the foregoingformula (2) and had phosphorus atom content of 7.59% by weight. In thefollowing, the phosphorus-containing carboxylic acid derivative thusobtained is referred to as Block acid I. In the same manner as inExample 1, the solubility test and the storage stability test werecarried out for the Block acid I. The results are shown in Table 1.

EXAMPLE 10 Phosphorus-Containing Carboxylic Acid Derivative Produced byModifying DPHP-ItaA with N-Propylvinyl Ether

A four-neck flask equipped with a reflux condenser, a stirrer and athermometer was charged with 63.8 parts by weight of DPHP-ItaA which hadbeen obtained in the Reference Example 7, and 36.2 parts by weight ofn-propylvinyl ether. The resultant mixture was stirred under theconditions of 10° C. for 6 hours. The reactivity which was calculatedfrom the measured acid value was 98.7%. Then unreacted n-propylvinylether was removed with the use of an evaporator under the conditions of20 mmHg and 50° C. (the acid value after the vacuum concentration being9.75 mg KOH/g).

The facts that the acid value of the product was remarkably low ascompared with that of the DPHP-ItaA before the reaction, and that anyabsorption assigned to the carboxylic group was not confirmed from theinfrared absorption spectrum have rendered it possible to confirm thatthe carboxylic group of the DPHP-ItaA was modified with then-propylvinyl ether. That is to say, the objective phosphorus-containingcarboxylic acid derivative has the structure represented by thefollowing formula (r):

The objective phosphorus-containing carboxylic acid derivative had inits one molecule, 2 functional groups represented by the foregoingformula (2) and had phosphorus atom content of 6.14% by weight.

In the following, the phosphorus-containing carboxylic acid derivativethus obtained is referred to as Block acid J.

In the same manner as in Example 1, the solubility test and the storagestability test were carried out for the Block acid J. The results areshown in Table 1. For the purpose of comparison, the M-Acid that hadbeen obtained in the Reference Example 3 was tested in the same manneras the above description.

TABLE 1 Solubility Test Stability Acetone MIBK AcN PMAc Toluene Ep 828Test Example. 1 Block Acid A AA AA AA AA AA AA AA Example. 2 Block AcidB AA AA AA AA AA AA AA Example. 3 Block Acid C AA AA AA AA AA AA AAExample. 4 Block Acid D AA AA AA AA AA AA AA Example. 5 Block Acid E AAAA AA AA BB AA AA Example. 6 Block Acid F AA AA AA AA BB AA AA Example.7 Block Acid G AA AA AA AA BB AA AA Example. 8 Block Acid H AA AA AA AABB AA AA Example. 9 Block Acid I AA AA AA AA AA AA AA Example. 10 BlockAcid J AA AA AA AA AA AA AA Ref. Example. 3 M-Acid BB CC CC CC CC CCGellation Marketed Product PBTC AA AA AA AA CC CC Hardened (15) Ref.Example. 5 DEHP-ItaA AA AA AA AA CC CC Hardened (5) Ref. Example. 7DEHP-ItaA AA AA AA AA CC CC Hardened (5){Remarks}

Regarding evaluation on the results of the solubility test, the marksmean as the following:

“AA” means compatible or completely soluble;

“BB” means that a certain turbidity was observed in the solution; and

“CC” means apparently not homogeneous.

Regarding evaluation on the results of the stability test, the marksmean as the following:

“AA” means no change observed on viscosity;

“Gellation” means that the sample rendered clear viscosity increase inthe fluid; and

“Hardened” means that a hardened product non-flowable in a vial evenwhen the vial was brought down, and the figure in parentheses showspasture of time before hardening expressed by minutes.

MIBK is an abbreviation of methyl isobutyl ketone.

AcN is an abbreviation of acetonitrile.

PMAc is an abbreviation of methoxypropyl acetate.

Ep828 is epoxy resin of bisphenol type A (available from Japan EpoxyResin Co., Ltd. under the trade name “Epicote 828”).

EXAMPLE 11 Preparation of Film Blended with Block Acid A

A resin composition was prepared by mixing and agitating in a vial, 5.54parts by weight of the Block acid A which had been synthesized inExample 1, 4.22 parts by weight of “YDPN 638” (trade name, availablefrom Touto Kasei Co., Ltd.; epoxy resin of phenol novolak type) and 0.21part by weight of “Nofcure-LC-1” (trade name, available from NOFCorporation; heat latent type catalyst).

Thereafter, the resin composition thus prepared was applied over a tinpanel {JIS G3303 (SPTE), available from Japan Test Panel Osaka Co.,Ltd.} with the use of a bar coater, followed by curing under theconditions of 200° C. for one hour to obtain a cured film of the resincomposition. Then the resultant cured film was peeled apart from the tinpanel to obtain a film A.

The film A was subjected to external appearance observation, solventresistance test, combustibility test, coloring observation and heatresistance test. The results are shown in Table 2.

EXAMPLE 12 Preparation of Film Blended with Block Acid B

A resin composition was prepared by mixing and agitating in a vial, 5.76parts by weight of the Block acid B which had been synthesized inExample 2, 4.06 parts by weight of YDPN 638 and 0.21 part by weight ofNofcure-LC-1.

Thereafter, the resin composition thus prepared was applied over the tinpanel with the use of the bar coater, followed by curing under theconditions of 200° C. for one hour to obtain a cured film of the resincomposition. Then the resultant cured film was peeled apart from the tinpanel to obtain a film B.

In the same manner as the film A, the film B was subjected to externalappearance observation, solvent resistance test, combustibility test,coloring observation and heat resistance test. The results are shown inTable 2.

EXAMPLE 13 Preparation of Film Blended with Block Acid C

A resin composition was prepared by mixing and agitating in a vial, 6.16parts by weight of the Block acid C which had been synthesized inExample 3, 3.60 parts by weight of YDPN 638 and 0.21 part by weight ofNofcure-LC-1.

Thereafter, the resin composition thus prepared was applied over the tinpanel with the use of the bar coater, followed by curing under theconditions of 200° C. for one hour to obtain a cured film of the resincomposition. Then the resultant cured film was peeled apart from the tinpanel to obtain a film C.

In the same manner as the film A, the film C was subjected to externalappearance observation, solvent resistance test, combustibility test,coloring observation and heat resistance test. The results are shown inTable 2.

EXAMPLE 14 Preparation of Film Blended with Block Acid D

A resin composition was prepared by mixing and agitating in a vial, 5.61parts by weight of the Block acid D which had been synthesized inExample 4, 4.09 parts by weight of YDPN 638 and 0.21 part by weight ofNofcure-LC-1.

Thereafter, the resin composition thus prepared was applied over the tinpanel with the use of a bar coater, followed by curing under theconditions of 200° C. for one hour to obtain a cured film of the resincomposition. Then the resultant cured film was peeled apart from the tinpanel to obtain a film D.

In the same manner as the film A, the film D was subjected to externalappearance observation, solvent resistance test, combustibility test,coloring observation and heat resistance test. The results are shown inTable 2.

EXAMPLE 15 Preparation of Film Blended with Block Acid A˜2

A resin composition was prepared by mixing and agitating in a vial, 4.57parts by weight of the Block acid A which had been synthesized inExample 1, 4.45 parts by weight of “Epicote 828” (trade name, availablefrom Japan Epoxy Resin Co., Ltd.; epoxy resin of bisphenol type A), 0.74part by weight of a derivative from CIC acid{tris(2-carboxyethyl)isocyanic acid} by n-propylvinyl ether and 0.21part by weight of Nofcure-LC-1.

Thereafter, the resin composition thus prepared was applied over the tinpanel with the use of the bar coater, followed by curing under theconditions of 200° C. for one hour to obtain a cured film of the resincomposition. Then the resultant cured film was peeled apart from the tinpanel to obtain a film A2.

In the same manner as the film A, the film A2 was subjected to externalappearance observation, solvent resistance test, combustibility test,coloring observation and heat resistance test. The results are shown inTable 2.

EXAMPLE 16 Preparation of Film Blended with Block Acid A˜3

A resin composition was prepared by mixing and agitating in a vial, 3.88parts by weight of the Block acid A which had been synthesized inExample 1, 4.51 parts by weight of Epicote 828, 1.36 part by weight of aderivative from CIC acid by n-propylvinyl ether and 0.21 part by weightof Nofcure-LC-1.

Thereafter, the resin composition thus prepared was applied over the tinpanel with the use of the bar coater, followed by curing under theconditions of 200° C. for one hour to obtain a cured film of the resincomposition. Then the resultant cured film was peeled apart from the tinpanel to obtain a film A3.

In the same manner as the film A, the film A3 was subjected to externalappearance observation, solvent resistance test, combustibility test,coloring observation and heat resistance test. The results are shown inTable 2.

EXAMPLE 17 Preparation of Film Blended with Block Acid A˜4

A resin composition was prepared by mixing and agitating in a vial, 2.51parts by weight of the Block acid A which had been synthesized inExample 1, 4.65 parts by weight of Epicote 828, 2.61 part by weight of aderivative from CIC acid by n-propylvinyl ether and 0.21 part by weightof Nofcure-LC-1.

Thereafter, the resin composition thus prepared was applied over the tinpanel with the use of the bar coater, followed by curing under theconditions of 200° C. for one hour to obtain a cured film of the resincomposition. Then the resultant cured film was peeled apart from the tinpanel to obtain a film A4.

In the same manner as the film A, the film A4 was subjected to externalappearance observation, solvent resistance test, combustibility test,coloring observation and heat resistance test. The results are shown inTable 2.

EXAMPLE 18 Preparation of Film Blended with Block Acid A˜5

A resin composition was prepared by mixing and agitating in a vial, 4.63parts by weight of the Block acid A which had been synthesized inExample 1, 4.54 parts by weight of Epicote 828, 0.60 part by weight of aderivative from trimellitic acid by n-propylvinyl ether and 0.21 part byweight of Nofcure-LC-1.

Thereafter, the resin composition thus prepared was applied over the tinpanel with the use of the bar coater, followed by curing under theconditions of 200° C. for one hour to obtain a cured film of the resincomposition. Then the resultant cured film was peeled apart from the tinpanel to obtain a film A5.

In the same manner as the film A, the film A5 was subjected to externalappearance observation, solvent resistance test, combustibility test,coloring observation and heat resistance test. The results are shown inTable 2.

EXAMPLE 19 Preparation of Film Blended with Block Acid A˜6

A resin composition was prepared by mixing and agitating in a vial, 3.93parts by weight of the Block acid A which had been synthesized inExample 1, 4.69 parts by weight of Epicote 828, 1.14 part by weight of aderivative from trimellitic acid by n-propylvinyl ether and 0.21 part byweight of Nofcure-LC-1.

Thereafter, the resin composition thus prepared was applied over the tinpanel with the use of the bar coater, followed by curing under theconditions of 200° C. for one hour to obtain a cured film of the resincomposition. Then the resultant cured film was peeled apart from the tinpanel to obtain a film A6.

In the same manner as the film A, the film A6 was subjected to externalappearance observation, solvent resistance test, combustibility test,coloring observation and heat resistance test. The results are shown inTable 2.

COMPARATIVE EXAMPLE 1 Preparation of Film 1 not Blended with Block AcidA

A resin composition was prepared by mixing and agitating in a vial, 5.06parts by weight of Epicote 828, 4.94 parts by weight of a derivativefrom CIC acid by n-propylvinyl ether and 0.21 part by weight ofNofcure-LC-1.

Thereafter, the resin composition thus prepared was applied over the tinpanel with the use of the bar coater, followed by curing under theconditions of 200° C. for one hour to obtain a cured film of the resincomposition. Then the resultant cured film was peeled apart from the tinpanel to obtain a film 1.

In the same manner as the film A, the film 1 was subjected to externalappearance observation, solvent resistance test, combustibility test,coloring observation and heat resistance test. The results are shown inTable 2.

COMPARATIVE EXAMPLE 2 Preparation of Film 2 Not Blended with Block AcidA

A resin composition was prepared by mixing and agitating in a vial, 5.69parts by weight of Epicote 828, 4.32 part by weight of a derivative fromtrimellitic acid by n-propylvinyl ether and 0.21 parts by weight ofNofcure-LC-1.

Thereafter, the resin composition thus prepared was applied over the tinpanel with the use of the bar coater, followed by curing under theconditions of 200° C. for one hour to obtain a cured film of the resincomposition. Then the resultant cured film was peeled apart from the tinpanel to obtain a film 2.

In the same manner as the film A, the film 2 was subjected to externalappearance observation, solvent resistance test, combustibility test,coloring observation and heat resistance test. The results are shown inTable 2.

COMPARATIVE EXAMPLE 3 Preparation of Film M Blended with UnmodifiedM-Acid)

An attempt was made to prepare a resin composition by mixing andagitating in a vial, 5.06 parts by weight of Epicote 828, 4.94 parts byweight of a derivative from CIC acid by n-propylvinyl ether, 20.0 partsby weight of unmodified M-Acid and 0.21 parts by weight of Nofcure-LC-1.However, the M-Acid was not dissolved, thereby forming non-homogeneousand opaque suspension.

Thereafter, the resultant suspension was applied over the tin panel withthe use of the bar coater, followed by curing under the conditions of200° C. for one hour to obtain a cured film of the resin composition.Then the resultant cured film was peeled apart from the tin panel toobtain a film M which was non-uniform, opaque and extremely brittle.

In the same manner as the film A, the film M was subjected to externalappearance observation, solvent resistance test, combustibility test,coloring observation and heat resistance test. The results are shown inTable 2.

EXAMPLE 20 Preparation of Film Blended with Block Acid E

A resin composition was prepared by mixing and agitating in a vial, 3.57parts by weight of the Block acid E which had been synthesized inExample 5, 2.70 parts by weight of YDPN 638 and 0.13 parts by weight ofNofcure-LC-1.

Thereafter, the resin composition thus prepared was applied over the tinpanel with the use of the bar coater, followed by curing under theconditions of 200° C. for one hour to obtain a cured film of the resincomposition. Then the resultant cured film was peeled apart from the tinpanel to obtain a film E.

In the same manner as the film A, the film E was subjected to externalappearance observation, solvent resistance test, combustibility test,coloring observation and heat resistance test. The results are shown inTable 2.

EXAMPLE 21 Preparation of Film Blended with Block Acid F

A resin composition was prepared by mixing and agitating in a vial, 3.48parts by weight of the Block acid F which had been synthesized inExample 6, 2.87 parts by weight of YDPN 638 and 0.13 part by weight ofNofcure-LC-1.

Thereafter, the resin composition thus prepared was applied over the tinpanel with the use of the bar coater, followed by curing under theconditions of 200° C. for one hour to obtain a cured film of the resincomposition. Then the resultant cured film was peeled apart from the tinpanel to obtain a film F.

In the same manner as the film A, the film F was subjected to externalappearance observation, solvent resistance test, combustibility test,coloring observation and heat resistance test. The results are shown inTable 2.

EXAMPLE 22 Preparation of Film Blended with Block Acid G

A resin composition was prepared by mixing and agitating in a vial, 3.61parts by weight of the Block acid G which had been synthesized inExample 7, 2.62 parts by weight of YDPN 638 and 0.14 part by weight ofNofcure-LC-1.

Thereafter, the resin composition thus prepared was applied over the tinpanel with the use of the bar coater, followed by curing under theconditions of 200° C. for one hour to obtain a cured film of the resincomposition. Then the resultant cured film was peeled apart from the tinpanel to obtain a film G.

In the same manner as the film A, the film G was subjected to externalappearance observation, solvent resistance test, combustibility test,coloring observation and heat resistance test. The results are shown inTable 2.

EXAMPLE 23 Preparation of Film Blended with Block Acid H

A resin composition was prepared by mixing and agitating in a vial, 4.37parts by weight of the Block acid H which had been synthesized inExample 8, 5.39 parts by weight of YDPN 638 and 0.21 part by weight ofNofcure-LC-1.

Thereafter, of the resin composition thus prepared was applied over thetin panel with the use of the bar coater, followed by curing under theconditions of 200° C. for one hour to obtain a cured film of the resincomposition. Then the resultant cured film was peeled apart from the tinpanel to obtain a film H.

In the same manner as the film A, the film H was subjected to externalappearance observation, solvent resistance test, combustibility test,coloring observation and heat resistance test. The results are shown inTable 2.

EXAMPLE 24 Preparation of Film Blended with Block Acid I

A resin composition was prepared by mixing and agitating in a vial, 4.96parts by weight of the Block acid I which had been synthesized inExample 9, 4.80 parts by weight of YDPN 638 and 0.21 part by weight ofNofcure-LC-1.

Thereafter, the resin composition thus prepared was applied over the tinpanel with the use of the bar coater, followed by curing under theconditions of 200° C. for one hour to obtain a cured film of the resincomposition. Then the resultant cured film was peeled apart from the tinpanel to obtain a film I.

In the same manner as the film A, the film I was subjected to externalappearance observation, solvent resistance test, combustibility test,coloring observation and heat resistance test. The results are shown inTable 2.

EXAMPLE 25 Preparation of Film Blended with Block Acid J

A resin composition was prepared by mixing and agitating in a vial, 5.48parts by weight of the Block acid J which had been synthesized inExample 10, 4.29 parts by weight of YDPN 638 and 0.21 part by weight ofNofcure-LC-1.

Thereafter, the resin composition thus prepared was applied over the tinpanel with the use of the bar coater, followed by curing under theconditions of 200° C. for one hour to obtain a cured film of the resincomposition. Then the resultant cured film was peeled apart from the tinpanel to obtain a film J.

In the same manner as the film A, the film J was subjected to externalappearance observation, solvent resistance test, combustibility test,coloring observation and heat resistance test. The results are shown inTable 2.

TABLE 2 P content Film Solvent Heat Film (% by wt) Appearance ResistanceUL94TM Coloring Resistance Example 11 A 4.1 AA AA V-0 AA AA Example 12 B3.5 AA AA V-0 AA AA Example 13 C 3 AA AA V-0 AA AA Example 14 D 2 AA AAV-0 AA AA Example 15 A2 3.5 AA AA V-0 AA AA Example 16 A3 3 AA AA V-0 AAAA Example 17 A4 4.1 AA AA V-0 AA AA Example 18 A5 4.1 AA AA V-0 AA AAExample 19 A6 4.1 AA AA V-0 AA AA Example 20 E 4.1 AA AA V-0 AA AAExample 21 F 4.1 AA AA V-0 AA AA Example 22 G 4.1 AA AA V-0 AA AAExample 23 H 3.8 Yellow & transparent AA V-0 AA AA Example 24 I 4.9Yellow & transparent AA V-0 AA AA Example 25 J 4.3 Yellow & transparentAA V-0 AA AA Comp. Example 1 1 0 AA AA CC CC CC Comp. Example 2 2 0 AAAA CC CC CC Comp. Example 3 M 1.5 Not uniform CC CC CC BB{Remarks}

“P content (% by wt)” means Phosphorus component with the dimension of %by weight calculated from blending composition.

Regarding Film appearance, it was visually observed and “AA” meanscolorless and transparent

Regarding the evaluation of Solvent resistance test, “AA” means freefrom defect and “CC” means that the film was apparently suffered fromdamages.

UL94TM indicates results of combustion test and “CC” meansnon-standardized.

Regarding the evaluation of the coloring observation, “AA” means withoutyellowing before and after heating and “CC” means with yellowingapparently confirmed before or after heating.

Regarding evaluation of the heat resistance test, “AA” means that thethermal decomposition temperature of the sample being 330° C. or higher,“BB” means that the thermal decomposition temperature of the samplebeing lower than 330° C. and at least 310° C., and “CC” means that thethermal decomposition temperature being lower than 310° C.

EXAMPLE 26 Preparation of Laminate A Using Block Acid A as FlameRetardant

A resin composition was prepared by mixing and agitating in a vial, 3.77parts by weight of the Block acid A which had been synthesized inExample 1, 3.24 parts by weight of “YDCN 701” (trade name, availablefrom Touto Kasei Co., Ltd.; epoxy resin of cresol novolak type), 0.35parts by weight of “Nofcure-LC-1” (trade name, available from NOFCorporation; heat latent type catalyst), and 3.90 parts by weight ofmethyl ethyl ketone.

Thereafter, the resin composition thus prepared was applied over Msurface of a copper foil “3EC-111” (trade name, available from MitsuiMining and Smelting Co., Ltd. and having the thickness of 18 μm) withthe use of the bar coater. After prebaking at 145° C. for 3 minutes, atack-free resin coated surface was obtained. Subsequently, three sheetsof the resultant resin coated foils were laminated so that the copperfoil and the resin coating were alternately superimposed, and theexposed resin coated surface was covered with S surface of the copperfoil, followed by curing with a press under pressing conditions of 180°C., 60 minutes and 200 kgf/cm². After the pressing, there was obtained alaminate in the form of plate having a film thickness of about 200 μm.

EXAMPLE 27 Preparation of LED Covered with Resin Composition Blendedwith Block Acid A

A resin composition was prepared by mixing and agitating in a vial, 4.70parts by weight of the Block acid A which had been synthesized inExample 1, 3.24 parts by weight of “EHPE-3150” (trade name, availablefrom Daicel Chemical Industries Ltd.; alicyclic epoxy resin in solidform), 0.40 part by weight of “Nofcure-LC-1” (trade name, available fromNOF Corporation; a heat latent type catalyst) and 5,40 parts by weightof methyl ethyl ketone.

Thereafter, an LED (light emitting diode, available on the market underthe trade name “NSPW310BS”) was dipped in the resin composition thusprepared, then dried at room temperature for 10 minutes, and heated at100° C. for one hour further at 120° C. for one hour. The covering filmthus obtained was colorless transparent, and had a film thickness ofabout 30 μm.

The covered LED was subjected to inflammation test by exposing the samein the blue flame of methane gas burner. A non-covered LED caught fireafter about 4 seconds from the start of the test, and completely burnteven when it was kept away from the flame. On the contrary, the coveredLED did not catch fire for about 25 seconds thereafter, and when it waskept at a distance after catching fire, the flame caught thereby wasself-extinguished.

INDUSTRIAL APPLICABILITY

The phosphorus-containing carboxylic acid derivative according to thepresent invention is utilized as a flame retardant, coloring preventiveagent and heat resistance-imparting agent, and for a resin moldedarticle, laminate, resin casting material, resin sealing material,adhesive, covering material and the like on the basis of suchcharacteristics that are imparted thereto as self and heatresistance-imparting agent, and for a resin molded article, laminate,resin casting material, resin sealing material, adhesive, coveringmaterial and the like on the basis of such characteristics that areimparted thereto as self fire-extinguishing property, flame retardancy,coloring preventiveness and heat resistance.

1. A phosphorus-containing carboxylic acid derivative which has a groupcontaining phosphorus atom and has in its molecule, a group representedby the following formula (2):

wherein R¹, R² and R³ are each hydrogen atom or a hydrocarbon grouphaving 1 to 18 carbon atoms, R⁴ is a hydrocarbon group having 1 to 18carbon atoms, R³ and R⁴ may be bonded to each other, and Y is oxygenatom or sulfur atom.
 2. A phosphorus-containing carboxylic acidderivative which has a group containing phosphorus atom and has in itsmolecule, a group represented by the following formula (3):

wherein R⁴ is a hydrocarbon group having 1 to 18 carbon atoms.
 3. Aphosphorus-containing carboxylic acid derivative which is apolyhemiacetal phosphorus-containing carboxylic acid derivative andcomprises, as a repeating unit, a group represented by the followingformula (4):

wherein R¹, R² and R³ are each hydrogen atom or a hydrocarbon grouphaving 1 to 18 carbon atoms, Y is oxygen atom or sulfur atom, R⁵ is abivalent organic group having 1 to 25 carbon atoms, and R⁶ is a bivalentorganic group which has 1 to 30 carbon atoms and comprises a groupcontaining phosphorus atoms.
 4. A phosphorus-containing carboxylic acidderivative which is a polyhemiacetal phosphorus-containing carboxylicacid derivative and comprises, as a repeating unit, a group representedby the following formula (5):

wherein R⁵ is a bivalent organic group having 1 to 25 carbon atoms, andR⁶ is a bivalent organic group which has 1 to 30 carbon atoms andcomprises a group containing phosphorus atom.
 5. Thephosphorus-containing carboxylic acid derivative according to claim 1,wherein said group containing phosphorus atom is represented by thefollowing formula (7)

wherein R⁷ is hydrogen atom or an organic group having 1 to 20 carbonatoms, R⁸ is an organic group having 1 to 20 carbon atoms, and when bothR⁷ and R⁸ are an organic group, they may be bonded to each other.
 6. Thephosphorus-containing carboxylic acid derivative according to claim 1,wherein said group containing phosphorus atom is represented by thefollowing formula (8):

wherein R⁹ and R¹⁰ are each hydrogen atom or an organic group having 1to 20 carbon atoms, and when both R⁹ and R¹⁰ are an organic group, theymay be bonded to each other.
 7. The phosphorus-containing carboxylicacid derivative according to claim 1, wherein said group containingphosphorus atom is represented by the following formula (10):

wherein X¹ to X⁸, which are each an atom or a group that may be the sameas or different from one another, are each hydrogen atom, a halogen atomor a hydrocarbon group having 1 to 5 carbon atoms.
 8. A flame retardantcomprising as an ingredient, the phosphorus-containing carboxylic acidderivative as set forth in claim
 1. 9. A process for producing aphosphorus-containing carboxylic acid derivative as set forth in claim1, which comprises a step of reacting a phosphorus-containing carboxylicacid compound bearing both a carboxylic group and phosphorus atom with avinyl ether compound, a vinyl thioether compound, a divinyl ethercompound or a divinyl thioether compound.
 10. The process for producinga phosphorus-containing carboxylic acid derivative according to claim 9,wherein said phosphorus-containing carboxylic acid compound is producedby subjecting (A) a P—H group-containing phosphorus compound and (B) anunsaturated carboxylic acid each as a starting raw material to Michaeladdition reaction by (i) using acetonitrile or methoxypropyl acetate asa principal reaction solvent at (ii) a reaction temperature in the rangeof 50 to 150° C.
 11. A resin composition which comprises (a) a syntheticresin bearing in its molecule, at least two reactive groups that areeach reactive with a carboxylic group and (b) the phosphorus-containingcarboxylic acid derivative as set forth in claim
 1. 12. The resincomposition according to claim 11, wherein said reactive groups are eachan epoxy group.
 13. A resin-molded article obtained by curing the resincomposition as set forth in claim
 11. 14. A laminated sheet comprising asubstrate and the resin-molded article as set forth in claim
 13. 15. Acovered article comprising a substrate and a covering layer formed byapplying said resin composition as set forth in claim 11 over at least apart of surfaces of said substrate.
 16. The covered article according toclaim 15, wherein said covering layer is further cured.
 17. Thephosphorus-containing carboxylic acid derivative according to claim 3,wherein said group containing phosphorus atom is represented by thefollowing formula (7)

wherein R⁷ is hydrogen atom or an organic group having 1 to 20 carbonatoms, R⁸ is an organic group having 1 to 20 carbon atoms, and when bothR⁷ and R⁸ are an organic group, they may be bonded to each other. 18.The phosphorus-containing carboxylic acid derivative according to claim3, wherein said group containing phosphorus atom is represented by thefollowing formula (8):

wherein R⁹ and R¹⁰ are each hydrogen atom or an organic group having 1to 20 carbon atoms, and when both R⁹ and R¹⁰ are an organic group, theymay be bonded to each other.
 19. The phosphorus-containing carboxylicacid derivative according to claim 3, wherein said group containingphosphorus atom is represented by the following formula (10):

wherein X¹ to X⁸, which are each an atom or a group that may be the sameas or different from one another, are each hydrogen atom, a halogen atomor a hydrocarbon group having 1 to 5 carbon atoms.
 20. A flame retardantcomprising as an ingredient, the phosphorus-containing carboxylic acidderivative as set forth in claim
 6. 21. A flame retardant comprising asan ingredient, the phosphorus-containing carboxylic acid derivative asset forth in claim
 5. 22. A flame retardant comprising as an ingredient,the phosphorus-containing carboxylic acid derivative as set forth inclaim
 3. 23. A flame retardant comprising as an ingredient, thephosphorus-containing carboxylic acid derivative as set forth in claim2.
 24. A process for producing a phosphorus-containing carboxylic acidderivative as set forth in claim 3, which comprises a step of reacting aphosphorus-containing carboxylic acid compound bearing both a carboxylicgroup and phosphorus atom with a vinyl ether compound, a vinyl thioethercompound, a divinyl ether compound or a divinyl thioether compound. 25.A resin composition which comprises (a) a synthetic resin bearing in itsmolecule, at least two reactive groups that are each reactive with acarboxylic group and (b) the phosphorus-containing carboxylic acidderivative as set forth in claim
 3. 26. The phosphorus-containingcarboxylic acid derivative according to claim 2, wherein said groupcontaining phosphorus atom is represented by the following formula (7):

wherein R⁷ is hydrogen atom or an organic group having 1 to 20 carbonatoms, R⁸ is an organic group having 1 to 20 carbon atoms, and when bothR⁷ and R⁸ are an organic group, they may be bonded to each other. 27.The phosphorus-containing carboxylic acid derivative according to claim2, wherein said group containing phosphorus atom is represented by thefollowing formula (8):

wherein R⁹ and R¹⁰ are each hydrogen atom or an organic group having 1to 20 carbon atoms, and when both R⁹ and R¹⁰ are an organic group, theymay be bonded to each other.
 28. The phosphorus-containing carboxylicacid derivative according to claim 2, wherein said group containingphosphorus atom is represented by the following formula (10):

wherein X¹ to X⁸, which are each an atom or a group that may be the sameas or different from one another, are each hydrogen atom, a halogen atomor a hydrocarbon group having 1 to 5 carbon atoms.
 29. A flame retardantcomprising as an ingredient, the phosphorus-containing carboxylic acidderivative as set forth in claim
 2. 30. A process for producing aphosphorus-containing carboxylic acid derivative as set forth in claim2, which comprises a step of reacting a phosphorus-containing carboxylicacid compound bearing both a carboxylic group and phosphorus atom with avinyl ether compound, a vinyl thioether compound, a divinyl ethercompound or a divinyl thioether compound.
 31. A resin composition whichcomprises (a) a synthetic resin bearing in its molecule, at least tworeactive groups that are each reactive with a carboxylic group and (b)the phosphorus-containing carboxylic acid derivative as set forth inclaim
 2. 32. A resin-molded article obtained by curing the resincomposition as set forth in claim
 31. 33. A laminated sheet comprising asubstrate and the resin-molded article as set forth in claim
 32. 34. Acovered article comprising a substrate and a covering layer formed byapplying said resin composition as set forth in claim 31 over at least apart of surfaces of said substrate.
 35. A phosphorus-containingcarboxylic acid derivative which has a group containing phosphorus atomand has in its molecule, a group represented by the following formula(1):

wherein R¹, R² and R³ are each hydrogen atom or a hydrocarbon grouphaving 1 to 18 carbon atoms, and Y is oxygen atom or sulfur atom, andwherein said group containing phosphorus atom is represented by thefollowing formula (10):

wherein X¹ to X⁸, which are each an atom or a group that may be the sameas or different from one another, are each hydrogen atom, a halogen atomor a hydrocarbon group having 1 to 5 carbon atoms.